I pulled your changes and the syntax highlighting looks better with your gherkin highlighting because quotes and everything inside quotes are highlighted, but it looks like the highlighting doesn't work properly if the string inside the quotes has line breaks.
Have you seen [https://github.com/schacon/showoff/pull/46] where cucumber syntax highlighting was added?
I pulled your changes and the syntax highlighting looks better with your gherkin highlighting because quotes and everything inside quotes are highlighted, but it looks like the highlighting doesn't work properly if the string inside the quotes has line breaks.