[3.13] gh-72239: Add note distinguishing concurrent.futures.Future from asyncio.Future (GH-143288) (#143608)

gh-72239: Add note distinguishing concurrent.futures.Future from asyncio.Future (GH-143288)
(cherry picked from commit a9ca49d9c699ce4040f1391d9054d88b4098466b)

Co-authored-by: AN Long <aisk@users.noreply.github.com>