Whitespace rationalisation of entire code base.

The number of people has been steadily increasing who read our source
code with an editor that thinks tab stops are 4 spaces apart, as
opposed to the traditional tty-derived 8 that the PuTTY code expects.

So I've been wondering for ages about just fixing it, and switching to
a spaces-only policy throughout the code. And I recently found out
about 'git blame -w', which should make this change not too disruptive
for the purposes of source-control archaeology; so perhaps now is the
time.

While I'm at it, I've also taken the opportunity to remove all the
trailing spaces from source lines (on the basis that git dislikes
them, and is the only thing that seems to have a strong opinion one
way or the other).
    
Apologies to anyone downstream of this code who has complicated patch
sets to rebase past this change. I don't intend it to be needed again.

doc/config.but

@@ -359,8 +359,8 @@ Most servers send two control characters, \i{CR} and \i{LF}, to start a
 left-hand side of the screen. The LF character makes the cursor move
 one line down (and might make the screen scroll).
 
-Some servers only send CR, and so the newly 
-written line is overwritten by the following line. This option causes 
+Some servers only send CR, and so the newly
+written line is overwritten by the following line. This option causes
 a line feed so that all lines are displayed.
 
 \S{config-erase} \q{Use \i{background colour} to erase screen}
@@ -1194,7 +1194,7 @@ characters should be treated as single-width for the purposes of \I{wrapping,
 terminal}wrapping and so on; however, in some CJK contexts, they are better
 treated as double-width for historical reasons, and some server-side
 applications may expect them to be displayed as such. Setting this option
-will cause PuTTY to take the double-width interpretation. 
+will cause PuTTY to take the double-width interpretation.
 
 If you use legacy CJK applications, and you find your lines are
 wrapping in the wrong places, or you are having other display
@@ -1508,7 +1508,7 @@ If you enable \q{Copy to clipboard in RTF as well as plain text},
 PuTTY will write formatting information to the clipboard as well as
 the actual text you copy. The effect of this is
 that if you paste into (say) a word processor, the text will appear
-in the word processor in the same \i{font}, \i{colour}, and style 
+in the word processor in the same \i{font}, \i{colour}, and style
 (e.g. bold, underline) PuTTY was using to display it.
 
 This option can easily be inconvenient, so by default it is
@@ -2053,7 +2053,7 @@ itself.
 
 Also, the special strings \c{%host} and \c{%port} will be replaced
 by the host name and port number you want to connect to. The strings
-\c{%user} and \c{%pass} will be replaced by the proxy username and 
+\c{%user} and \c{%pass} will be replaced by the proxy username and
 password you specify. The strings \c{%proxyhost} and \c{%proxyport}
 will be replaced by the host details specified on the \e{Proxy} panel,
 if any (this is most likely to be useful for the Local proxy type).
@@ -2064,8 +2064,8 @@ before commands can be sent, you can use a command such as:
 
 \c %user\n%pass\nconnect %host %port\n
 
-This will send your username and password as the first two lines to 
-the proxy, followed by a command to connect to the desired host and 
+This will send your username and password as the first two lines to
+the proxy, followed by a command to connect to the desired host and
 port. Note that if you do not include the \c{%user} or \c{%pass}
 tokens in the Telnet command, then the \q{Username} and \q{Password}
 configuration fields will be ignored.
@@ -3565,13 +3565,13 @@ once it's been successfully saved back to the file.
 Here is \c{PUTTYDEL.REG}:
 
 \c REGEDIT4
-\c  
+\c
 \c [-HKEY_CURRENT_USER\Software\SimonTatham\PuTTY]
 
 Here is an example \c{PUTTYRND.REG} file:
 
 \c REGEDIT4
-\c  
+\c
 \c [HKEY_CURRENT_USER\Software\SimonTatham\PuTTY]
 \c "RandSeedFile"="a:\\putty.rnd"
 

doc/errors.but

@@ -193,7 +193,7 @@ Various forms of this error are printed in the PuTTY window, or
 written to the PuTTY Event Log (see \k{using-eventlog}) during
 authentication.
 
-If you see one of these messages, it means that the server has refused 
+If you see one of these messages, it means that the server has refused
 all the forms of authentication PuTTY has tried and it has no further
 ideas.
 
@@ -231,7 +231,7 @@ noticed.
 
 Occasionally this has been caused by server bugs. An example is the
 bug described at \k{config-ssh-bug-hmac2}, although you're very
-unlikely to encounter that one these days. 
+unlikely to encounter that one these days.
 
 In this context MAC stands for \ii{Message Authentication Code}. It's a
 cryptographic term, and it has nothing at all to do with Ethernet

doc/faq.but

@@ -166,7 +166,7 @@ will not. Adding an option to turn host key checking off completely is
 the wrong solution and we will not do it.
 
 If you have host keys available in the common \i\c{known_hosts} format,
-we have a script called 
+we have a script called
 \W{https://git.tartarus.org/?p=simon/putty.git;a=blob;f=contrib/kh2reg.py;hb=HEAD}\c{kh2reg.py}
 to convert them to a Windows .REG file, which can be installed ahead of
 time by double-clicking or using \c{REGEDIT}.
@@ -241,7 +241,7 @@ present time. If anyone told you we had an Android port, or an iOS
 port, or any other port of PuTTY, they were mistaken. We don't.
 
 There are some third-party ports to various platforms, mentioned
-on the 
+on the
 \W{https://www.chiark.greenend.org.uk/~sgtatham/putty/links.html}{Links page of our website}.
 
 \S{faq-unix}{Question} \I{Unix version}Is there a port to Unix?
@@ -991,7 +991,7 @@ means you need to use non-\cw{127.0.0.1} addresses to forward
 Terminal Services in the first place.)
 
 \S{faq-missing-slash}{Question} PSFTP commands seem to be missing a
-directory separator (slash). 
+directory separator (slash).
 
 Some people have reported the following incorrect behaviour with
 PSFTP:

doc/feedback.but

@@ -148,7 +148,7 @@ information:
 use the \q{About PuTTY} option from the System menu. Please \e{do
 not} just tell us \q{I'm running the latest version}; e-mail can be
 delayed and it may not be obvious which version was the latest at
-the time you sent the message. 
+the time you sent the message.
 
 \b PuTTY is a multi-platform application; tell us what version of what
 OS you are running PuTTY on. (If you're running on Unix, or Windows
@@ -218,7 +218,7 @@ Secure Contact Key. See \k{pgpkeys-pubkey} for details of this.
 much information as possible about them, the same way you would with
 any other bug report.)
 
-\H{feedback-features} Requesting extra features 
+\H{feedback-features} Requesting extra features
 
 If you want to request a new feature in PuTTY, the very first things
 you should do are:

doc/plink.but

@@ -290,7 +290,7 @@ zero exit status if a usable \q{upstream} exists, nonzero otherwise.
 In some situations, Plink applies a sanitisation pass to the output
 received from the server, to strip out control characters such as
 backspace and the escape character.
-    
+
 The idea of this is to prevent remote processes from sending confusing
 escape sequences through the standard error channel when Plink is
 being used as a transport for something like \cw{git} or CVS. If the
@@ -418,7 +418,7 @@ labelled \q{Check for an alternate \cw{rsh} name} and in the text
 entry field to the right enter the full path to \c{plink.exe}.
 Select \q{OK} on the \q{Preferences} dialogue box.
 
-Next, select \q{Command Line} from the WinCVS \q{Admin} menu, and type 
+Next, select \q{Command Line} from the WinCVS \q{Admin} menu, and type
 a CVS command as in \k{plink-cvs}, for example:
 
 \c cvs -d :ext:user@hostname:/path/to/repository co module

doc/pscp.but

@@ -78,7 +78,7 @@ familiar with that.)
 
 \S{pscp-usage-basics} The basics
 
-To \I{receiving files}receive (a) file(s) from a remote server: 
+To \I{receiving files}receive (a) file(s) from a remote server:
 
 \c pscp [options] [user@]host:source target
 
@@ -87,7 +87,7 @@ user \c{fred} to the file \c{c:\\temp\\example-hosts.txt}, you would type:
 
 \c pscp fred@example.com:/etc/hosts c:\temp\example-hosts.txt
 
-To \I{sending files}send (a) file(s) to a remote server: 
+To \I{sending files}send (a) file(s) to a remote server:
 
 \c pscp [options] source [source...] [user@]host:target
 
@@ -146,7 +146,7 @@ trying to get out of that directory using pathnames including
 \S2{pscp-usage-basics-user} \c{user}
 
 The \i{login name} on the remote server. If this is omitted, and \c{host}
-is a PuTTY saved session, PSCP will use any username specified by that 
+is a PuTTY saved session, PSCP will use any username specified by that
 saved session.  Otherwise, PSCP will attempt to use the local Windows
 username.
 
@@ -160,8 +160,8 @@ number, cipher type and username will be used.
 
 One or more source files. \ii{Wildcards} are allowed.  The syntax of
 wildcards depends on the system to which they apply, so if you are
-copying \e{from} a Windows system \e{to} a UNIX system, you should use 
-Windows wildcard syntax (e.g. \c{*.*}), but if you are copying \e{from} 
+copying \e{from} a Windows system \e{to} a UNIX system, you should use
+Windows wildcard syntax (e.g. \c{*.*}), but if you are copying \e{from}
 a UNIX system \e{to} a Windows system, you would use the wildcard
 syntax allowed by your UNIX shell (e.g. \c{*}).
 
@@ -179,7 +179,7 @@ target of \c{.}.  For example:
 
 \c pscp fred@example.com:/home/tom/.emacs .
 
-...would copy \c{/home/tom/.emacs} on the remote server to the current 
+...would copy \c{/home/tom/.emacs} on the remote server to the current
 directory.
 
 As with the \c{source} parameter, if the target is on a remote server
@@ -235,7 +235,7 @@ these statistics.
 
 By default, PSCP will only copy files.  Any directories you specify to
 copy will be skipped, as will their contents.  The \c{-r} option tells
-PSCP to descend into any directories you specify, and to copy them and 
+PSCP to descend into any directories you specify, and to copy them and
 their contents.  This allows you to use PSCP to transfer whole
 directory structures between machines.