CodeMirror 4.9

In addition to updating the CodeMirror Javascript and css files, this update exposes a new CodeMirror option via the plugin's configuration screen in the Joomla! administrator. It's a minor thing, you can now select a scrollbar style. 

Oh, and CodeMirror 4.9 also includes 2 new dark themes so maybe one of them appeals to someone. 
the CS issue is here:

`id="'. ` we need a space after the `"'`and bevor the dot :smile: