[skip actions]

The fix for CTracer is egregious and will need to be updated when there's a
supported way to do it.

The fullcoverage skip is noted in
https://github.com/nedbat/coveragepy/issues/1278

The raise_through_with skip is noted in
https://github.com/nedbat/coveragepy/issues/1270

.. and also add trailing commas where needed to remove ambiguity.

I used semgrep with this config:
```
rules:
  - id: implicit-string-concatenation
    pattern: |
      "$X" "$Y"
    languages:
      - python
    message: string cat BAD
    severity: INFO
```

Running it showed this:

```
$ semgrep --config=../lab/string-cat.yml coverage tests doc ci igor.py setup.py __main__.py
Running 1 rules...
setup.py
severity:info rule:lab.implicit-string-concatenation: string cat BAD
128:            'https://tidelift.com/subscription/pkg/pypi-coverage'
129:            '?utm_source=pypi-coverage&utm_medium=referral&utm_campaign=pypi'

tests/test_api.py
severity:info rule:lab.implicit-string-concatenation: string cat BAD
319:            "!coverage.py: This is a private format, don't read it directly!"
320:            '{"lines":{"/private/tmp/foo.py":[1,5,2,3]}}'

tests/test_html.py
severity:info rule:lab.implicit-string-concatenation: string cat BAD
614:            ('<span class="key">if</span> <span class="num">1</span> '
615:             '<span class="op">&lt;</span> <span class="num">2</span>'),
--------------------------------------------------------------------------------
616:            ('    <span class="nam">a</span> '
617:             '<span class="op">=</span> <span class="num">3</span>'),
--------------------------------------------------------------------------------
665:            ('<span class="key">if</span> <span class="nam">x</span> '
666:             '<span class="op">&lt;</span> <span class="num">2</span>'),
--------------------------------------------------------------------------------
667:            ('    <span class="nam">a</span> <span class="op">=</span> '
668:             '<span class="num">3</span>'),
--------------------------------------------------------------------------------
949:            ('<span class="key">if</span> <span class="num">1</span> '
950:             '<span class="op">&lt;</span> <span class="num">2</span>'),
--------------------------------------------------------------------------------
951:            ('    <span class="nam">a</span> <span class="op">=</span> '
952:             '<span class="num">3</span>'),
ran 1 rules on 134 files: 8 findings
```

This wasn't all of the instances, so I wrote a bug report: https://github.com/returntocorp/semgrep/issues/4184

This makes exceptions report their causes correctly, as "The above exception was
the direct cause of the following exception" instead of "During handling of the
above exception, another exception occurred."

* Support TOML v1.0.0 syntax in `pyproject.toml`

fixes #1180

Co-authored-by: Taneli Hukkinen <3275109+hukkin@users.noreply.github.com>

* fix toml meta test

* use pytest.mark.parametrize to narrow test failure

* Update tests/test_config.py

Co-authored-by: Taneli Hukkinen <3275109+hukkin@users.noreply.github.com>

Co-authored-by: Taneli Hukkinen <3275109+hukkin@users.noreply.github.com>

Python 4 doesn't exist, this requirement is redundant