use support.rmtree instead of shutil (closes #19614)

Patch by Sean Rodman.
add Sean Rodman
use ssl.PROTOCOL_SSLv23 for maximum compatibility (closes #20896)
merge 3.2 (#20896)
Fix note markup (#16805).

Patch by Tshepang Lekhonkhobe, reviewed by Georg Brandl.
remove unnecessary word (closes #19060)

Patch by Anastasia Filatova.
weaken callback count inequality (closes #20901)