patch 9.0.1991: no cmdline completion for setting the font

Problem:  no cmdline completion for setting the font
Solution: enable it on Win32 and GTK builds

Add guifont cmdline completion (for Windows and GTK)

For Windows, auto-complete will only suggest monospace fonts as that's
the only types allowed. Will also suggest font options after the colon,
including suggesting the current font size for convenience, and misc
charset and quality options like `cANSI` and `qCLEARTYPE`.

For GTK, auto-complete will suggest only monospace fonts for `guifont`
but will include all fonts for `guifontwide`. The completion code
doesn't currently suggest the current font size, as the GTK guifont
format does not have a clear delimiter (':' for other platforms).

closes: #13264

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>
diff --git a/src/version.c b/src/version.c
index 0f73dc2..9b1c0b4 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1991,
+/**/
     1990,
 /**/
     1989,