- YouCompleteMe is unnecessary since Nvim LSP works well. - vim-addon-local-vimrc is not needed since we added `.editorconfig`. - Inline flake8 arguments. Eventually we will remove all python code, don't need a top-level `.flake8` file meanwhile.
Ref: https://github.com/neovim/neovim/pull/10631#issuecomment-515756591