[3.12] gh-101100: Fix references to ``URLError`` and ``HTTPError`` in ``howto/urllib2.rst`` (GH-107966) (#110086)

gh-101100: Fix references to ``URLError`` and ``HTTPError`` in ``howto/urllib2.rst`` (GH-107966)
(cherry picked from commit bfd94ab9e9f4055ecedaa500b46b0270da9ffe12)

Co-authored-by: Yuki K <drsuaimqjgar@gmail.com>
Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com>