[FR] Use nvim builtin LSP client by --enable_lsp

[bottob]

Code like

codeium.nvim/lua/codeium/source.lua

Line 152 in d3b88eb

local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, true)

tries to get all content of files will be called on every completion request and will significantly slow down editor.

By communicating with LSP, we could use text document sync feature to enable incremental updates of opened files and avoid ineffcient operations like retriving all files content on client side.