Include additional VHDL syntax rules - Linting

You can use the sigasi (http://www.sigasi.com/) editor : it prints keywords in bold and uses different shades of gray for other words. You can change these settings to your own likings.

And it also formats and indents your code, the only drawback is that you cannot change the formatting rules (I keep on asking Sigasi to change this ...). The good thing is that this also works in the 'free' version. You may want to print to a pdf-file using A3 (or some user-define size of) paper to get a reasonable page-filling.