Support a real Luau lexer

[CompeyDev]

Is there an existing issue for this?

• I have searched the existing issues

What is the missing lexer?

Currently, there is no Luau lexer, and Luau files are simply aliased to the Lua lexer as per #1056. The correct implementation would be to have a real Luau lexer for the Luau language, which has significantly diverged from Lua.

Such an alias tends to often misbehave for syntax highlighting due to how similar tokens can have entirely different meanings in contexts -- and has been evident in the past when users used to use .gitattributes overrides to alias Luau to Lua before official support was landed in GitHub's Linguist library.

Links to existing syntax definitions

There is a community maintained repository containing Textmate language files, which the Linguist library also uses: JohnnyMorganz/Luau.tmLanguage.