Missing `src/tree_sitter/parse.rh` breaks SPM

[feifanzhou]

Hey @DerekStride,
30732ef removes src/tree_sitter/parser.h, which is required in Package.swift and makes this package usable in Swift projects. Any objection to bringing back that src/tree_sitter/parser.h file?

[thecoolwinter]

Seconding this!

[matthias-Q]

Do you also need the parser.c or just parser.h