docs-bug(all): More robust set of harnesses and their practical uses

[andrewseguin]

Documentation Feedback

Test harnesses are really great, but it's difficult to grasp the practicality of using them, especially when it comes to using the "with" options and the filters. Practical examples on each component documentation page would help a lot, e.g. find a harness based on an ancestor selector, or finding a button with certain text.

Affected documentation page

All component pages

[amysorto]

It would also be great if as a part of this, we can have a new tab for testing to make the documentation more discoverable.