doc: QFontMetrics::elidedText(...) does not work as expected for ElideNone

Issue: QFontMetrics::elidedText(myString, Qt::ElideNone, myWidth) returns myString (i.e., unchanged), even if myString does not fit into myWidth (code works fine with Qt::ElideRight).
Expected return value: truncated myString, so that it just fills myWidth (without ellipsis appended).
Solution: either change/correct the implementation. Or, if this is intentional, please clarify in the documentation that Qt::ElideNone does not only prevent an ellipsis to be appended, but disables string clipping altogether.