patch 9.1.1138: cmdline completion for :hi is too simplistic

Problem:  Existing cmdline completion for :highlight was barebone and
          only completed the highlight group names.

Solution: Implement full completion for the highlight group arguments
          such as guifg and cterm. If the user tries to complete
          immediately after the '=' (e.g. `hi Normal guifg=<Tab>`), the
          completion will fill in the existing value, similar to how
          cmdline completion for options work (Yee Cheng Chin).

closes: #16712

Signed-off-by: Yee Cheng Chin <ychin.git@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 0851aa5..0ada1b2 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -1,4 +1,4 @@
-*eval.txt*	For Vim version 9.1.  Last change: 2025 Jan 29
+*eval.txt*	For Vim version 9.1.  Last change: 2025 Feb 23
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -2081,7 +2081,7 @@
 
 		You can make changes to that file, but make sure to add new
 		keys instead of updating existing ones, otherwise Vim will skip
-		loading the file (thinking is hasn't been changed).
+		loading the file (thinking it hasn't been changed).
 
 				*v:completed_item* *completed_item-variable*
 v:completed_item