Highlight hex colors in string literals

[OndrejSpanel]

Is your feature request related to a problem? Please describe.

In my Scala sources colors are highlighted fine when written as hex literals, like 0xAFE154, but not when written in a string literals, like "#AFE154".

Describe the solution you'd like

I would like colors which follow the web format (i.e. starting with # and having six hex digits) to be highlighted in String literals as well.