Use String#each_char instead of String#chars

[ydah]

Fix: #100

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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).

[bquorning]

Maybe we should add https://github.com/rubocop/rubocop-rubycw to Gemfile. Would that have caught the issue earlier?

[ydah]

I checked this PR below and it looks like it doesn't support jruby.

• Add rubocop-rubycw #102

[bquorning]

I mean, it’s weird if String#chars has a different API in CRuby and JRuby.

[ydah]

String#chars has a deprecated warning until Ruby 2.6, but the warning seems to have been removed in Ruby 2.7. However, the warning continues to appear in jruby.

[pirj]

RSpec’s own spec suite checks if there were any warnings, and fails if so.
That would be our option if we want to be warning-free.

[pirj]

Thanks!