.. note::

   $ find sphinx tests LICENSE doc/conf.py -type f -exec sed -i '' -e 's/2007\-20../2007-2021/' {} \;
   $ git co sphinx/locale/**/*.js sphinx/templates/epub3/mimetype

Keep imports alphabetically sorted and their order homogeneous across
Python source files.

The isort project has more feature and is more active than the
flake8-import-order plugin.

Most issues caught were simply import ordering from the same module.
Where imports were purposefully placed out of order, tag with
isort:skip.

I found test-root defines rst_epilog in its conf.py.  It causes
side-effects to many test cases in Sphinx's testing because test-root
is widely used.  This removes the configuration from test-root not to
cause side-effects to our testings.

Note: We already have test cases for rst_epilog in test_util_rst.

Since pygments-2.7.0, it has changed the style of output HTML.
That makes our test broken.  This fixes it to pass with new pygments.

To make EPUB output valid, remove a search link from test-root.

This slightly tweaks the regex so that command line flags of the form
foo[=N] are properly split up. This is useful for any programs that can
take `--foo` as a flag on its own as well as with an extra argument
`--foo=12`.