Add Prolog tree-sitter grammar

[mkorje]

This PR adds a tree-sitter grammar for Prolog. It uses https://codeberg.org/foxy/tree-sitter-prolog, a fork/rewrite of https://github.com/Rukiza/tree-sitter-prolog.

I've probably made a mistake in how the runtime/queries/prolog/* files should be done, sorry about that! The changes in this PR seem to be working for me, though I'd appreciate it if others could try it out and ensure it works for them.