Support adding / ignoring unknown keywords

[Lexicality]

trafficstars

I'm working on a modified version of lua that added the continue keyword and I want to format files that contain it. Either a config option to add new keywords or an option to treat unknown keywords like return would be very useful.

[tammela]

You may modify the Lua.g4 grammar to your tweaks and it should work just fine

[Lexicality]

I can definitely do that, but maintaining a fork sounds like a chore

[Jarod42]

Similarly, premake uses some functions to "open" block. Wonder if it could be handled in some way.