Add a new Capybara/NegationMatcherAfterVisit cop

[ydah]

Resolve: #7

This PR adds a new Capybara/NegationMatcherAfterVisit cop.

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Before submitting the PR make sure the following are checked:

• Feature branch is up-to-date with main (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Updated documentation.
• Added an entry to the CHANGELOG.md if the new code introduces user-observable changes.
• The build (bundle exec rake) passes (be sure to run this locally, since it may produce updated documentation that you will need to commit).

If you have created a new cop:

• Added the new cop to config/default.yml.
• The cop is configured as Enabled: pending in config/default.yml.
• The cop documents examples of good and bad code.
• The tests assert both that bad code is reported and that good code is not reported.
• Set VersionAdded: "<<next>>" in default/config.yml.

[jdufresne]

I recently diagnosed and then fixed code in my project that would have benefited from this cop. Any thing I can do to help move it along?

[jdufresne]

I recently diagnosed and then fixed code in my project that would have benefited from this cop. Any thing I can do to help move it along?

In case it helps, I rebased your work to resolve the merge conflicts: #140

But if this PR resumes, I'm happy to close it in favor of this one.

[pirj]

@boris-petrov does this look right to you?

@ydah can you please rebase?

[ydah]

Rebased this PR

[pirj]

Thank you! 🙌

[ydah]

I will wait for @jdufresne response this question before merging.

[pirj]

What question exactly? I can’t find anything blocking. What am I missing?