In particular, `DiagnosticPopover` both:
* Supports moving the selection to a diagnostic when clicked, based on
`group_id`
* Provides Diagnostic values with `group_id: 0` providing informztion on
hover about invisible characters.
So, clicking such a popover would navigate to the very first error
produced by a language server. Really not a big deal of course, but
seems good to fix as it might result in surprising behavior in other
future circumstances
Release Notes:
- N/A
Michael Sloan
3ae6aa0e4d