Accessibility: Improve fuzzy finder description
Created by: umpox
Description
Closes https://github.com/sourcegraph/sourcegraph/issues/35247
Just updates the description to make it clear that this is the fuzzy finder - as there's not an obvious action that opens it (could be triggered through keyboard press)
Test plan
Tested locally with a screen reader
App preview:
Check out the client app preview documentation to learn more.
