Replace deprecated `vim.loop` calls with `compat.uv`.

[mrcjkb]

          note to self (for another issue): `vim.loop` will be deprecated in Neovim 0.10 (replaced with `vim.uv`). Use `require('rustaceanvim.compat').uv` instead (the existing `vim.loop` calls are ones I forgot to fix when I forked the project).

Originally posted by @mrcjkb in #64 (comment)

[mrcjkb]

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