Update runtime files.
diff --git a/runtime/ftplugin/jsonc.vim b/runtime/ftplugin/jsonc.vim
index 90d52cd..e47a75f 100644
--- a/runtime/ftplugin/jsonc.vim
+++ b/runtime/ftplugin/jsonc.vim
@@ -4,7 +4,7 @@
 " Acknowledgement:  Based off of vim-jsonc maintained by Kevin Locke <kevin@kevinlocke.name>
 "                   https://github.com/kevinoid/vim-jsonc
 " License:          MIT
-" Last Change:      2021-07-01
+" Last Change:      2021 Nov 22
 
 runtime! ftplugin/json.vim
 
@@ -14,14 +14,8 @@
   let b:did_ftplugin_jsonc = 1
 endif
 
-" A list of commands that undo buffer local changes made below.
-let s:undo_ftplugin = []
-
 " Set comment (formatting) related options. {{{1
 setlocal commentstring=//%s comments=sO:*\ -,mO:*\ \ ,exO:*/,s1:/*,mb:*,ex:*/,://
-call add(s:undo_ftplugin, 'commentstring< comments<')
 
 " Let Vim know how to disable the plug-in.
-call map(s:undo_ftplugin, "'execute ' . string(v:val)")
-let b:undo_ftplugin = join(s:undo_ftplugin, ' | ')
-unlet s:undo_ftplugin
+let b:undo_ftplugin = 'setlocal commentstring< comments<'