While std::vector::assign() returns void, std::basic_string::assign()
returns std::basic_string&. In Qt, we want to be consistent between
{QVLA,QList,QString,QByteArray}::assign(), and returning *this is the
more general solution, so do that.
Task-number: QTBUG-106196
Task-number: QTBUG-106200
Change-Id: I2689b4af032ab6fb3f8fbcb4d825d5201ea5abeb
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
8712e35aec