runtime(heex): Add HEEX comments to match_words in ftplugin (#12957)

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/heex.vim b/runtime/ftplugin/heex.vim
index f79c69d..becc071 100644
--- a/runtime/ftplugin/heex.vim
+++ b/runtime/ftplugin/heex.vim
@@ -18,7 +18,7 @@
 " HTML: thanks to Johannes Zellner and Benji Fisher.
 if exists("loaded_matchit") && !exists("b:match_words")
   let b:match_ignorecase = 1
-  let b:match_words = '<!--:-->,' ..
+  let b:match_words = '<%\{-}!--:--%\{-}>,' ..
 	\	      '<:>,' ..
 	\	      '<\@<=[ou]l\>[^>]*\%(>\|$\):<\@<=li\>:<\@<=/[ou]l>,' ..
 	\	      '<\@<=dl\>[^>]*\%(>\|$\):<\@<=d[td]\>:<\@<=/dl>,' ..