Private Use Area characters are quite valid input characters when used
in combination with a custom font. Joiners also serve an important language
purpose in semitic writing systems.
Note that there is a hack where we disregard any character produced
using CTRL or CTRL+SHIFT specifically because of German keyboards. I have chosen to
keep the hack in this patch to limit the change (though I have made an exception
for ZWJ and ZWNJ since both are produced using Ctrl+Shift on Windows), but it
will probably have to be reverted.
[ChangeLog][QtWidgets][Input] Accept characters in Private Use Area, as well as
zero-width joiners and zero-width non-joiners in input in QLineEdit and QTextEdit.
Task-number: QTBUG-42074
Task-number: QTBUG-57003
Change-Id: I73f3b7d587a8670de24e902dc52a51f7721dba5a
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
7896ae052a