[ChangeLog][Important Behavior Changes] QDebug output for QStrings
changed compared to Qt 5.5.0 to more closely match the output of
previous Qt versions. Like Qt 5.5.0, QDebug will escape non-printable
characters, the backslash and quote characters, but will no longer
escape the printable characters.
Task-number: QTBUG-47316
Change-Id: I52dd43c12685407bb9a6ffff13f62ef68cbc80c5
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>