@moklick thanks for reporting. The plugin works on our side although we have received a couple more reports of the plugin not working correctly for some people.
A few questions:
Are you on Sketch 48.1 or 48.2?
Which version of macOS are you on?
Is the code not being properly colored in any theme or just a specific one?
Have you tried disabling and enabling the plugin again?
since the last sketch update the plugin doesn't seem to work anymore. The background gets the right color but the font doesn't change.