fix(lsp): fix relative patterns for `workspace/didChangeWatchedFiles`
(cherry picked from commit 10f102a3a3)
Co-authored-by: Jon Huhn <huhnjon@gmail.com>
Fixes:
Error SERVER_REQUEST_HANDLER_ERROR: "...di/dev/neovim/neovim/runtime/lua/vim/lsp/_watchfiles.lua
:200: bad argument #1 to 'ipairs' (table expected, got nil)"
Language servers can be started without root_dir or workspace_folders.
