Announce the correct line when on the end of a link at the end of a list item in a contenteditable (#11606)
* MozillaCompoundTextInfo: when trying to normalize the caret position at the end of an inline element, make sure not to search above the deepest non-inline element. This stops accidentally falling out of the current paragraph or list item etc and then inappropriately reading the next line instead of the current.
* Fix linting issues
* Add system test.
* Fix linting issue
* Make comment more explicit.
Co-authored-by: Reef Turner <feerrenrut@users.noreply.github.com>
* Update what's new
Co-authored-by: Reef Turner <feerrenrut@users.noreply.github.com>