Like QTextDocument::toRawText(), QTextDocumentFragment::toRawText()
does allow access to the raw string without normalizing nbsp,
line separator, paragraph separator unicode characters.
[ChangeLog][QtGui][Text] Added QTextDocumentFragment::toRawText() function.
Task-number: QTBUG-99572
Change-Id: Ia74150a3870ea0e6326fdcda4d9d0410019124ae
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>