Formatting: normalise back to 4-space indentation.

In several pieces of development recently I've run across the
occasional code block in the middle of a function which suddenly
switched to 2-space indent from this code base's usual 4. I decided I
was tired of it, so I ran the whole code base through a re-indenter,
which made a huge mess, and then manually sifted out the changes that
actually made sense from that pass.

Indeed, this caught quite a few large sections with 2-space indent
level, a couple with 8, and a handful of even weirder things like 3
spaces or 12. This commit fixes them all.

windows/dialog.c

@@ -582,9 +582,9 @@ static INT_PTR GenericMainDlgProc(HWND hwnd, UINT msg, WPARAM wParam,
 
                 c = strrchr(s->pathname, '/');
                 if (!c)
-                        c = s->pathname;
+                    c = s->pathname;
                 else
-                        c++;
+                    c++;
 
                 item = treeview_insert(&tvfaff, j, c, s->pathname);
                 if (!hfirst) {