improve dev setup comments and hints

[4imothy]

What does this PR do?

Changes 'pip install -e .[dev]' -> `pip install -e '.[dev]'` in multiple comments and hints.

New command runs on both zsh and bash, previously it did not work on zsh.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline,
  Pull Request section?
• Was this discussed/approved via a Github issue or the forum? Please add a link
  to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the
  documentation guidelines, and
  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

Documentation: @stevhliu and @MKhalusova

[amyeroberts]

Thanks for updating!

[amyeroberts]

For the failing tests, you'll need to update the expected strings.