Now that it's possible for a single invocation of PuTTY to connect to
multiple SSH servers (jump host followed by ultimate destination
host), it's rather unhelpful for host key prompts to just say "the
server". To check an unknown host key, users will need to know _which_
host it's purporting to be the key for.
Another possibility is to put a message in the terminal window
indicating which server we're currently in the SSH setup phase for.
That will certainly be what we have to end up doing for userpass
prompts that appear _in_ the terminal window. But that by itself is
still unhelpful for host key prompts in a separate dialog, because the
user would have to check both windows to get all the information they
need. Easier if the host key dialog itself tells you everything you
need to know to answer the question: is _this_ key the one you expect
for _that_ host?
The format _strings_ were previously centralised into the platform-
independent console.c, as const char arrays. Now the actual formatting
operation is centralised as well, by means of console.c providing a
function that takes all the necessary parameters and returns a
formatted piece of text for the console.
Mostly this is so that I can add extra parameters to the message with
some confidence: changing a format string in one file and two fprintf
statements in other files to match seems like the kind of situation
you wish you hadn't got into in the first place :-)
The assorted host-key and warning prompt messages have no reason to
differ between the two platforms, so let's centralise them. Also,
while I'm here, some basic support functions that are the same in both
modules.
