One common source of flakiness is just dispatching a keybinding and
not verifying it did its thing. This change adds a few accept functions
and also forces callers to provide an async function so that the caller
considers adding one as it's the norm, not the edge case.
Fixes#246731
* Highlight label should not create extra empty dom nodes
I noticed that the `HighlightedLabel` class creates extra `span` elements for text ranges. These should not be needed. Using text children directly should be faster for creation and also reduce the number of nodes in the document
I also related the conditional spread with a longer version that uses a simple call to push. This is worth doing since `HighlightedLabel` is so widely used in the editor
* Update tests
* Update smoke test selector
* Update css
