[Fix #11122] Add new Style/RedundantLineContinuation cop

[ydah]

Fix: #11122

---

Before submitting the PR make sure the following are checked:

• The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.

[koic]

This cop should be able to detect various redundat \ cases such as:

def foo \
end

class Foo \
end

foo do \
end

and many cases.

[bbatsov]

@ydah I see a lot of CI failures.

[ydah]

Thank you so much for feedback. I updated this PR. on_new_investigation and added test cases and comments accordingly.

[ydah]

Thank you for lots. I updated this PR.

[bbatsov]

Seems we're good to go here. Thanks!

[nobuyo]

In looking at the release notes for v1.49, I noticed that the changelog entry on this was missing 👀

[ydah]

I also noticed that just now and opened the following PR.

• Add missing changes to the CHANGELOG and release note #11751

[gsamokovarov]

Here is an example of a false-positive case:

merged_document.public_url.should eq \
  "#{Settings.server.base_uri}/file_download?filename=graphql_receipts_merge%2Ftest1234"

Gets autocorrect to:

merged_document.public_url.should eq
"#{Settings.server.base_uri}/file_download?filename=graphql_receipts_merge%2Ftest1234"

This is interpreted as eq() by Ruby itself and fails my test.

merged_document.public_url.should eq()
"#{Settings.server.base_uri}/file_download?filename=graphql_receipts_merge%2Ftest1234"

I have to put parentheses to preserve the correct behaviour now, but I actually preferred omitting them in that case.

[koic]

@gsamokovarov Thanks! I've opened #11752 to fix the false positive.

[frodsan]

I think there is a false positive:

def ==(other)
        foo == other.foo \
          && bar == other.bar \
          &&  baz == other.baz
end

I get the following after autocorrect:

F: Lint/Syntax: unexpected token tAMPER
(Using Ruby 3.2 parser; configure using TargetRubyVersion parameter, under AllCops)
        && bar == other.bar

def ==(other)
        foo == other.foo \
          && bar == other.bar
          &&  baz == other.baz
end

[ydah]

@frodsan Thank you so much. I've opened #11754 to fix the false positive.