This introduces a new `result.isSuggestedIndexRelativeToGroup` property. When
true, `result.suggestedIndex` is relative to the result's group.
We can get rid of some hardcoded quick-suggest things with this.
I considered a `relativeSuggestedIndex` property that would replace
`suggestedIndex`, but it would have made `muxer._addSuggestedIndexResults` a
little more complex because it would need to know whether it should use
`relativeSuggestedIndex` or `suggestedIndex`. `UrlbarView._rowCanUpdateToResult`
would also need to be updated since it checks for suggestedIndex results. But
there are trade-offs either way and I'm open to using `relativeSuggestedIndex`.
While working on this I noticed that we broke the position of quick suggest
results in bug 1662167. They're supposed to be last in the outer general group,
and currently the muxer is hardcoded to put them last in `GENERAL`, but after
that bug `INPUT_HISTORY` actually comes last. To fix that I added a new
`GENERAL_PARENT` group that's used for the outer general group. Quick suggest
results now use this group, combined with a relative `suggestedIndex`, to come
last. I wanted to rename `GENERAL` to `PLACES` or `BOOKMARKS_HISTORY` and use
`GENERAL` for the outer group, but we use `GENERAL` in a ton of places (tests
especially) and I didn't want to touch blame for it all. I'm open to better
names than `GENERAL_PARENT`. I considered `FIREFOX_SUGGEST` but I don't think
it's a good idea to tie it to specific branding that may change.
Differential Revision: https://phabricator.services.mozilla.com/D122799
364162f4bf