QPainter should have drawString with QStringView

QPainter should have drawString to draw using QStringView.

For example, if I have long QString and want to draw some substrings from this string. This substrings is temporary objects that using only for drawing. So in paintEvent created many temporary strings. It can be avoided if draw substrings of QString using QStringView(or QStringRef in qt5) constructed from part of QString.