QMimeType: don't document the constructor that takes a Private class

Change-Id: I238e1eca6938deb728085a5416220230d9e751c7
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

src/corelib/mimetypes/qmimetype.cpp

@@ -140,6 +140,7 @@ QMimeType &QMimeType::operator=(const QMimeType &other)
 /*!
     \fn QMimeType::QMimeType(const QMimeTypePrivate &dd);
     Assigns the data of the QMimeTypePrivate \a dd to this QMimeType object, and returns a reference to this object.
+    \internal
  */
 QMimeType::QMimeType(const QMimeTypePrivate &dd) :
         d(new QMimeTypePrivate(dd))