Write tree-sitter scanners in Rust

[24bitnataliecuthbert]

I'm working on a language extension that needs support for a custom tree-sitter scanner. I'd like to be able to ideally write the scanner in Rust, however Zed's add-on build tool attempts to locate and build scanner.c and parser.c, making the use of Rust a non-starter.

The most practical solution to this request seems to be adding support for optionally providing a pre-built WASM file instead of the scanner source, though I'm sure there are other ideas that could achieve the same result...