Add some QChar::unicode() calls to brush over deprecation warning

Change-Id: I16383254373289584818cd2b590d51d9e4a649c5
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

src/widgets/widgets/qwidgetlinecontrol.cpp

@@ -112,7 +112,7 @@ void QWidgetLineControl::updateDisplayText(bool forceUpdate)
     // characters)
     QChar* uc = str.data();
     for (int i = 0; i < (int)str.length(); ++i) {
-        if ((uc[i] < 0x20 && uc[i] != 0x09)
+        if ((uc[i].unicode() < 0x20 && uc[i].unicode() != 0x09)
             || uc[i] == QChar::LineSeparator
             || uc[i] == QChar::ParagraphSeparator
             || uc[i] == QChar::ObjectReplacementCharacter)