Fix #7 - Error opening a .jsonc file

Author: zhmars

ftplugin/jsonc.vim

@@ -6,14 +6,8 @@ else
   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
+" Set comment (formatting) related options.
 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<'