[3.13] Doc: Recommend shlex.quote alongside pipes removal (GH-126570) (#126820)

Doc: Recommend shlex.quote alongside pipes removal (GH-126570)

One of the most common reasons I see the old `pipes` module still in use
when porting to Python 3.13 is for the undocumented `pipes.quote`
function, which can easily be replaced with `shlex.quote`.  I think it's
worth specifically calling this out, since being directed to the
`subprocess` module would be confusing in this case.
(cherry picked from commit 73e34b680852794d110cd806505b3d74d9d593db)

Co-authored-by: Colin Watson <cjwatson@debian.org>