Replace a few more QString::fromLatin1() with _s literals

Wasn't done in 7d79b94db7

Pick-to: 6.4
Task-number: QTBUG-98434
Change-Id: Id9c26f6b58e2c96a1c5f72154b735b136c57debc
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>

src/widgets/widgets/qwidgettextcontrol.cpp

@@ -3433,9 +3433,9 @@ void QUnicodeControlCharacterMenu::menuActionTriggered()
 QStringList QTextEditMimeData::formats() const
 {
     if (!fragment.isEmpty())
-        return QStringList() << QString::fromLatin1("text/plain") << QString::fromLatin1("text/html")
+        return QStringList() << u"text/plain"_s << u"text/html"_s
 #ifndef QT_NO_TEXTODFWRITER
-            << QString::fromLatin1("application/vnd.oasis.opendocument.text")
+            << u"application/vnd.oasis.opendocument.text"_s
 #endif
         ;
     else