[3.14] gh-141473: Document not calling Popen.wait after Popen.communicate times out. (GH-142101) (#142124)

gh-141473: Document not calling Popen.wait after Popen.communicate times out. (GH-142101)

Document not calling Popen.wait after Popen.communicate times out.

Closes GH-141473
(cherry picked from commit 3e2c55749326809a2fc76b9f2cb87a6f89037ebe)

Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com>