Doc: Fix QJniObject::construct() documentation

Even though QDoc accepted the \fn signature without a class scope,
the documentation does not end up on the class reference unless we
mark construct() as a member of QJniObject.

Pick-to: 6.4
Change-Id: Icae44f8eb24aa6b269242084479e735f2637c312
Reviewed-by: Luca Di Sera <luca.disera@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/corelib/kernel/qjniobject.cpp

@@ -762,7 +762,7 @@ QJniObject::QJniObject(jobject object)
 }
 
 /*!
-    \fn template<typename Class, typename ...Args> static inline QJniObject construct(Args &&...args)
+    \fn template<typename Class, typename ...Args> static inline QJniObject QJniObject::construct(Args &&...args)
     \since 6.4
 
     Constructs an instance of the Java class that is the equivalent of \c Class and