semi-vibed, need to clean up to match code conventions.
- replace all the `Result`s with `anyhow::Result`s
- I don't like that `LSPClient::setup` returns both a server and a client,
seems like it should just be at the root of the `lsp` module
- gotta remove a bunch of lints that are annoying and eating tokens
- gotta remove all the dumb agent comments
- eventually we'll have to be clever about de-allocating memory,
since at this point the LRU strategy used by `OpenedDocuments` never actually
deallocates. This logic will have to happen in `BufPool.`
- move the `LanguageId` type to its own module
- I think we should refactor all file access to go through the LSP, i.e.,
`OpenedDocuments` should be able to read the document into a buffer or something, and
this should probably be accessed through `LSPServer`.
Basically, the read tool itself will be very minimal. This ensures that all the LSP
bookkeeping and doc synchronization is handled correctly.