Remove an example which is a syntax error in Ruby's parser

[ydah]

This code generates a syntax error as follows:

❯ ruby -e '[1].each { put _1; [1].each { put _1 } }'
-e: -e:1: syntax error found (SyntaxError)
> 1 | ... _1 } }
    |     ^~ numbered parameter is already used in outer block

When numbered parameters are used in nested blocks, it is not possible to use numbered parameters in multiple different hierarchies.

While it was considered to split these up, we discussed below.
#2014 (comment)

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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.

If you have modified an existing cop's configuration options:

• Set VersionChanged: "<<next>>" in config/default.yml.

[pirj]

Thank you! ❤️