runtime(kconfig): updated ftplugin and syntax script

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/kconfig.vim b/runtime/ftplugin/kconfig.vim
index 7674907..1c2857e 100644
--- a/runtime/ftplugin/kconfig.vim
+++ b/runtime/ftplugin/kconfig.vim
@@ -2,7 +2,7 @@
 " Vim syntax file
 " Maintainer:		Christian Brabandt <cb@256bit.org>
 " Previous Maintainer:	Nikolai Weibull <now@bitwi.se>
-" Latest Revision:	2024-04-12
+" Latest Revision:	2025 Jan 20
 " License:		Vim (see :h license)
 " Repository:		https://github.com/chrisbra/vim-kconfig
 
@@ -19,4 +19,5 @@
 " For matchit.vim
 if exists("loaded_matchit")
   let b:match_words = '^\<menu\>:\<endmenu\>,^\<if\>:\<endif\>,^\<choice\>:\<endchoice\>'
+  let b:undo_ftplugin .= "| unlet! b:match_words"
 endif