Issue #22723: Make link styling more accessible.

Patch by Buck Golemon.

--HG--
branch : 3.4
Issue #22596: support.transient_internet() now also catches
ConnectionRefusedError exceptions wrapped by urllib.error.URLError.

This change should fix sporadic failures in test_urllib2net.

--HG--
branch : 3.4
Issue #22711: improve links in new distribution docs

- key term hyperlinks for distutils, setuptools & wheel
- distutils landing page links directly to setuptools docs
- short summary of setuptools benefits provided with link

--HG--
branch : 3.4
extra : amend_source : 28f6700f38efb820dbcfff2a60ee529709736067