UI: Enable search for stories and fix / event listener

[ghengeveld]

Issues: #13943 #13877 #13463

What I did

This enables searching for story names. When both a story and component are found and they're parent/child, only the first one is displayed (whichever ranks higher), to avoid multiple results that lead to the same place.

Additionally, this fixes the event listener for /. Turns out we had two competing listeners. I removed the custom one and fixed the core one to also select the input text.

How to test

• Is this testable with Jest or Chromatic screenshots? no
• Does this need a new example in the kitchen sink apps? no
• Does this need an update to the documentation? no

If your answer is yes to any of these, please make sure to include it in your PR.

[shilman]

Awesome 😍