chore: update language on how to test section

[Ignigena]

• The title of the PR is formatted according to the semantic commit guidelines
• Tests for the changes have been added (for bug fixes / features)
• Functionality has been verified and is ready to be tested

What is the new behavior?

The "How to Test" section is especially important for some PR to describe nuances around manually testing the new feature outside of Production. It is not intended to replace the "How to Demo" part of the issue requirements, but I've noticed that in some cases it's being referred to almost exclusively.

I've kept the section in place but reworded things a bit to re-iterate the importance of How to Demo and how this section should be used to help the PR process rather than serving as a source of truth for requirements.

Feel free to bikeshed the nuances of my language -- this was a very rough first stab 😄

Other information

Does this PR introduce a breaking change? No

[joelpalmer]

I think we discussed this a bit when I originally added it. The audience for the How to Demo section in the Issue is primarily the author or possibly a product person. The audience for the How to Test section in the PR is the Code Reviewers. At least that is how I have understood it.

So, I think your additional wording really makes that distinction clear and states what types of content we would like to see in that section. We have been and will continue to stress the importance of testing beyond the happy path. 👍🏼

Perfect! 🎸