QStringLiteral documentation still uses 'u' and has a caveat on it

Minor issue but has led to some confusion.

Documentation still has https://doc.qt.io/qt-6/qstring.html#QStringLiteral using the 'u' literal but from the code it seems it is always added anyway:

https://github.com/qt/qtbase/blob/6.4.1/src/corelib/text/qstringliteral.h

https://github.com/qt/qtbase/blob/5.15.2/src/corelib/text/qstringliteral.h

Is this note still valid?

Note: Some compilers have bugs encoding strings containing characters outside the US-ASCII character set. Make sure you prefix your string with u in those cases. It is optional otherwise.