Restore docs for Lint/UselessElseWithoutRescue

[pirj]

When running rake update_cops_documentation, this cop's docs keep being added.

The cop was removed in #10577, and after a fix for Ruby code parsing in RuboCop 1.29.1, was restored in #10697
But the docs were left out.

Please pardon my ignorance if the missing docs are filled in during the new version release process. I'm scratching my itch of getting rid of unrelated changes when I run rake update_cops_documentation when developing on a branch branched off of master.
Please don't hesitate to close this PR, as I can definitely live with git checkout --patch, and this is a temporary hiccup.

---

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.

[pirj]

The PR restoring this cop was one day late for 1.30.1.

[koic]

I’ll close this PR. Please see #10718 for details. Thank you.