Adding support for new languages

Not an issue per se, but not sure where else to ask questions? Sorry.

I'm trying to add support for Jai. The intent is to build a Jai static library that can be linked into a C++ program. I've managed to cobble together a `jai_static_library` that successfully produces `foo.lib`. I've added that as a `dep` to my C++ executable.

What I haven't been able to figure out is how to get `foo.lib` passed as a linker argument for the C++ executable. Presumably I need to put something into a `Provider`. But I'm not sure what or how.

Related, it would be nice if the [Writing Rules](https://buck2.build/docs/rule_authors/writing_rules/) documentation page was a little more complete. Right now it's an incomplete assortment of snippets. It'd be nice if it at least included at the bottom complete files.