Black doesn't warn about long lines inside function docstrings

[MVrachev]

Description of issue or feature request:
After we merged #1815 I noticed multiple lines inside function docstrings are over 80 characters.
Then I run a local scan with black (version 22.1.0) and I thought black will raise an error or format them, but nothing happened. Then, I proceeded to delete my local tox cache and run tox -e lint, but nothing happen again.

Some examples of long lines inside tuf/api/metadata.py:

• python-tuf/tuf/api/metadata.py

  Line 619 in d4dd652

  """Creates a ``Key`` object from a securesystemlib key dict representation

• python-tuf/tuf/api/metadata.py

  Line 763 in d4dd652

  consistent_snapshot: ``True`` if repository supports consistent snapshots.

• 1138 -1142:

  python-tuf/tuf/api/metadata.py

  Line 1138 in d4dd652

  - ``paths`` is set: delegates targets matching any path pattern in ``paths``

• python-tuf/tuf/api/metadata.py

  Line 1251 in d4dd652

  The ``target_filepath`` and the ``DelegatedRole`` paths are expected to be

Note that when there are long lines with normal code black does raise an error or format them.