Add new RSpec/RedundantPredicateMatcher cop

[ydah]

Fix: #1689

---

Before submitting the PR make sure the following are checked:

• Feature branch is up-to-date with master (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 is configured as Enabled: true in .rubocop.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.

[pirj]

Fantastic! Thank you!

[pirj]

Broke on:

      expect(json[:submissions]).to be_all do |ss|
        ss.key?("submission_history") && ss["submission_history"].empty?
      end

with:

undefined method `send_type?' for nil:NilClass
/Users/pirj/source/rubocop-rspec/lib/rubocop/cop/rspec/redundant_predicate_matcher.rb:47:in `replacable_arguments?'
/Users/pirj/source/rubocop-rspec/lib/rubocop/cop/rspec/redundant_predicate_matcher.rb:27:in `on_send'

Wondering why if node.parent.block_type? didn't work 🤔

[pirj]

Otherwise:

57497 files inspected, 883 offenses detected, 742 offenses autocorrectable

🎉

False positive? match takes a mandatory argument.

/Users/pirj/source/real-world-rspec/gitlabhq/spec/lib/gitlab/zoom_link_extractor_spec.rb:30:58: C: [Correctable] RSpec/RedundantPredicateMatcher: Use match instead of be_match.
        expect(described_class.new('issue text')).not_to be_match
                                                         ^^^^^^^^

module Gitlab
  class ZoomLinkExtractor
    # ...
    def match?
      ZOOM_REGEXP.match?(@text)
    end

Notes for future cops:

expect(json.count).to be_equal 1
expect(json[0]["group_submissions"]).to be_equal nil
expect(effective_paths.size).to be_eql(1)

[ydah]

Sorry for the delay. I updated this PR with the following corrections:
#1694 (comment)
#1694 (comment)

[pirj]

Thank you!