Fix mark.it titles when used with mark.parametrize

[RomuloOliveira]

Allow use of custom titles using pytest.mark.it along with parametrized tests. Fixes #22.

When mark.parametrize is used, pytest includes the parameters in the last part of nodeid (e.g. test_module_name.py::test_a_passing_test[this is a param]).
I used the fact that function names cannot contain brackets to safely extract parameters. Parameters may include brackets, though.

I think function names and arguments I wrote may need a more thorough review.

[RomuloOliveira]

@cartertinney could you please test if this will do the job for the cases you're working on? You can test using pip install git+https://github.com/renanivo/pytest-testdox.git@ro-mark-it-parametrize-fix.

@renanivo I've marked as a draft pull request until you or @cartertinney can confirm that it work as expected.

Here the output for some tests I did:

    @pytest.mark.parametrize('a_param', [
        'String',
        1234,
        [],
        {}
    ])
    @pytest.mark.it('It should display a nice name')
    def test_foobar(self, a_param):
        assert True

Include Parametrized
 ✓ It should display a nice name[String]
 ✓ It should display a nice name[1234]
 ✓ It should display a nice name[a_param2]
 ✓ It should display a nice name[a_param3]

Without using pytest-testdox, this is the output with -vv:

tests/test_formatters.py::TestIncludeParametrized::test_foobar[String] PASSED                                              [ 25%]
tests/test_formatters.py::TestIncludeParametrized::test_foobar[1234] PASSED                                                [ 50%]
tests/test_formatters.py::TestIncludeParametrized::test_foobar[a_param2] PASSED                                            [ 75%]
tests/test_formatters.py::TestIncludeParametrized::test_foobar[a_param3] PASSED                                            [100%]

[codecov]

Codecov Report

Merging #23 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #23   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           5      5           
  Lines         185    193    +8     
=====================================
+ Hits          185    193    +8

Impacted Files	Coverage Δ
pytest_testdox/formatters.py	100% <100%> (ø)	⬆️
pytest_testdox/models.py	100% <100%> (ø)	⬆️

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[renanivo]

Looks Great! 👏

[cartertinney]

Yeah, just tried it out, working great here. Thanks a bunch. 💯