runtime(doc): Add missing 'wfb' (winfixbuf) tag

closes: #17455

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index 4471b7c..bb91558 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.1.  Last change: 2025 Jun 04
+*options.txt*	For Vim version 9.1.  Last change: 2025 Jun 05
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -9870,7 +9870,7 @@
 	Note: Do not confuse this with the height of the Vim window, use
 	'lines' for that.
 
-						*'winfixbuf'*
+						*'winfixbuf'* *'wfb'*
 'winfixbuf' 'wfb'	boolean	(default off)
 			local to window
 	If enabled, the window and the buffer it is displaying are paired.