Fix deprecation warnings in nvim 0.10

[aarondill]

This fixes several deprecation warnings in nvim 0.10.
It should still work in previous versions.

• fix: vim.lsp.buf_get_clients is deprecated
• fix: vim.loop is deprecated
• fix: vim.api.nvim_buf_get_option is deprecated

[amirbilu]

@aarondill thanks for the contribution. Was it tested on previous versions?

[aarondill]

I've tested everything except for the chat changes (which should still work) on NVIM v0.9.5 built from source, as well as NVIM v0.11.0-dev-49+g10601ac5f (latest HEAD).
I don't use the chat, and I don't want to go through the trouble of making it work on my machine. If you'd like to test it, feel free, but vim.bo has existed since at least NVIM v0.5.0 (see neovim/neovim@43956de where it is already included in the docs).

Obviously the change in the readme is not backwards compatible, so older users still need to change it back to vim.loop. I can add a note if you'd like, but I think it's fine with vim.uv

[amirbilu]

Can you elaborate on needed in readme? Not sure I got this point

[aarondill]

@amirbilu In the README, I changed the reference to vim.loop.os_uname() to vim.uv.os_uname() for the "platform dependant build script". If one were to copy that code and use it before nvim 0.10.0, it would error.
If you want, I can add a note in the readme saying this and telling anyone running pre-0.10 to replace vim.uv with vim.loop

[amirbilu]

Got you

[amirbilu]

LGTM
If you can please add a comment in the README + document somewhere to remove the fallback once vim.loop is deprecated

[aarondill]

@amirbilu I added the note to the readme in 84768b0