runtime(doc): remove deprecation warning for gdefault

Deprecated can be misunderstood as being slated for removal; slightly
change wording to be clearer.

Signed-off-by: dundargoc <gocdundar@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/options.txt

@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.0.  Last change: 2023 Nov 20
+*options.txt*	For Vim version 9.0.  Last change: 2023 Dec 16
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -3838,9 +3838,9 @@ A jump table for the options with a short description can be found at |Q_op|.
 		:s///gg		  subst. all	  subst. one
 
 	NOTE: This option is reset when 'compatible' is set.
-	DEPRECATED: Setting this option may break plugins that are not aware
-	of this option.  Also, many users get confused that adding the /g flag
-	has the opposite effect of that it normally does.
+	Setting this option may break plugins that rely on the default
+	behavior of the 'g' flag. This will also make the 'g' flag have the
+	opposite effect of that documented in |:s_g|.
 	This option is not used in |Vim9| script.
 
 						*'grepformat'* *'gfm'*