Offer types (and maybe vars/attributes) for completion

[FourierTransformer]

Since we are using tree-sitter we know what is being typed when a completion request comes in. There's a note in misc_handlers.tl to not try and provide type resolution, but it might be worth looking into while typing simple_type, var (which i think are local and global), and "attributes" (or what <const> and <total> are referred to as, I can't quite recall)

https://github.com/teal-language/teal-language-server/blob/2dad2a7b90aad2911c646b4d6c130cd67349b941/src/teal_language_server/misc_handlers.tl#L211-L215