Report the update of the selection when using Word selection extend / reduce commmands (`f8` or `shift+f8`) (#17424)
Partially fixes #3293.
Summary of the issue:
When using f8 (extend selection) or shift+f8 (reduce selection) in Word, the selection changes are not reported.
Description of user facing changes
When using f8 (extend selection) or shift+f8 (reduce selection) in Word, the selection changes will now be reported.
If the selection is extended / reduced at both ends, two consecutive selection update messages are reported, as done for control+a (select all).
Description of development approach
In WordDocument.initOverlayClass, bind script_caret_changeSelection to f8 and shift+f8, as already done for other gestures such as alt+shift+home or alt+shift+pageDown.