Fix warnings: Fix outdated doc: Connecting to nvim through python REPL.

After neovim/python-client@b8b48bbe8fe9ee41ad73c9bd5a45e808504399e2,
docs were no longer relevant.
Merge pull request #1373 from elmart/fix-outofdate-doc

Fix outdated doc: Connecting to nvim through python REPL.