Darglint

Added

- There is now a Flake8 flag exposing the ignore regex option. This will
allow you to ignore a given file/set of files based on a regex during
a CI pipeline, etc. Thanks to AdamGleave for the pull request!

Changed

- Removed logging for some aspects of analysis, and an assertion from the
raise visitor. They were a little overly-broad, and it was causing some
integration tests to fail when run against new repos.

Added

- We now ignore return, pass, yield, and raise in abstract methods.
Thanks to maltevesper!

Fixed

- Resolved most of the mypy issues in the repository. This is mostly a
code cleanliness issue.

Added

- We now recognize property methods on a class, and there are options to ignore
properties for checking. Thanks to saroad2!

Added

- Added an option to ignore the presence of certain exceptions. This is
useful if your project has a common error which you don't want to have to
document everywhere (for example, a custom assertion error.) This can be
used through the `ignore_raise` configuration option, or command-line option.
Thanks to palt0 for the pull request!
- Added `ignore_regex` as a command-line option (this already existed as a
configuration option, but I overlooked it as a command-line option.) Thanks
to saroad2 for the pull request!

Changed

- Deprecated Python3.5 support, since it breaks the Travis CI build. I've left
the dockerfile test for it in, as everything still works.
- Added Python3.9 support.

Fixed

- Changed *config.cfg* to *setup.cfg* in the pre-commit documentation, which was
the correct name. Thanks to nuno-andre for the pull request.
- Load the `enable` option from the configuration file, so that disabled-by-default
errors can be shown. Thanks to palt0 for the pull request!

Fixed

- Bare returns now do not have to be documented. This aligns better with
expectations for docstrings, and matches what darglint did prior to refactoring
to handle nested functions.

Changed

- Refactored some enumerations into their own files, and moved strictness
checks to the base docstring method. Thanks to skarzi for the pull requests!
It makes the code a good deal cleaner.

Fixed

- Lambdas no longer result in erroneous arguments in the docstring.
Lambdas apparently reuse the Arguments ast node, which means that, since they
were scoped in the same function, they were adding erroneous arguments.
By moving lambdas into their own scope, we resolve that issue. Of course,
if a lambda raises an exception, we will no longer catch that in the
function description. However, doing that seems far less likely, and not
worth the excess logic to handle.