runtime(doc): Add :defe[r] shortname spec and tag

closes: #18281

Signed-off-by: Doug Kearns <[email protected]>
Signed-off-by: Christian Brabandt <[email protected]>

Author: dkearns

runtime/doc/tags

@@ -2530,6 +2530,7 @@ $quote	eval.txt	/*$quote*
 :def	vim9.txt	/*:def*
 :defc	vim9.txt	/*:defc*
 :defcompile	vim9.txt	/*:defcompile*
+:defe	userfunc.txt	/*:defe*
 :defer	userfunc.txt	/*:defer*
 :del	change.txt	/*:del*
 :delc	map.txt	/*:delc*

runtime/doc/userfunc.txt

@@ -1,4 +1,4 @@
-*userfunc.txt*	For Vim version 9.1.  Last change: 2025 Aug 06
+*userfunc.txt*	For Vim version 9.1.  Last change: 2025 Sep 12
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -393,8 +393,8 @@ is used as a method: >
 ==============================================================================
 
 3. Cleaning up in a function ~
-							*:defer*
-:defer {func}({args})	Call {func} when the current function is done.
+							*:defe* *:defer*
+:defe[r] {func}({args})	Call {func} when the current function is done.
 			{args} are evaluated here.
 
 Quite often a command in a function has a global effect, which must be undone