fix syntax of code example in docs: hierarchy-separator

[aurmer]

Issue: n/a

What Changed

• add a closing quote on string of code example in docs
• run yar update-all which added a trailing comma on the same code example

Checklist

Check the ones applicable to your change:

• [X] Ran yarn update-all
• [ ] Tests are updated
• [X] Documentation is updated

Change Type

Indicate the type of change your pull request is:

• [ ] maintenance
• [X] documentation
• [ ] patch
• [ ] minor
• [ ] major

[yannbf]

Great catch @aurmer, thank you so much for your contribution!

[github-actions[bot]]

:rocket: PR was released in v0.5.7 :rocket: