When using a braille display and text is selected on the current line (e.g. when searching in a text editor for text which occurs on the same line), the braille display will be scrolled if appropriate.
On a pending caret move if there is no cursor, try to scroll the braille display to the selection.
* Move the marking of a selection to braille.Region.
* Add Region.brailleSelectionStart/End.
* If there is a selection but not a cursor, e.g. in a TextInfoRegion, scroll the braille display to the selection start.
Fixes #5410.