doc: Remove indistinguishable declaration

QTimer contains a template member function callOnTimeout(), which accepts
a variable number of arguments. Because it is difficult to document such
a general function, several specific declarations were added under the
guard Q_CLANG_QDOC that represent the typical ways this function is used.
They are easier to document because they have specific signatures.

Unfortunately, the clang parser recognizes two of them as being the same,
so this change removes one of the two. It also adjusts the documentation
of the remaining one so that it indicates both uses.

Change-Id: Ifa7bed9093bd1491b7bfe154990864454885c003
Reviewed-by: Martin Smith <martin.smith@qt.io>

src/corelib/kernel/qtimer.cpp

@@ -585,29 +585,16 @@ void QTimer::singleShot(int msec, Qt::TimerType timerType, const QObject *receiv
 */
 
 /*!
-    \fn template<typename Functor> QMetaObject::Connection callOnTimeout(QObject *context, Functor functor, Qt::ConnectionType connectionType = Qt::AutoConnection)
+    \fn template<typename Functor> QMetaObject::Connection callOnTimeout(QObject *context, Functor function, Qt::ConnectionType connectionType = Qt::AutoConnection)
     \since 5.12
     \overload callOnTimeout()
 
-    Creates a connection from the timeout() signal to \a functor to be placed in a specific
-    event loop of \a context, and returns a handle to the connection.
+    Creates a connection from the timeout() signal to \a function, which could be a pointer
+    to a member function of \a context, or it could be a functor to be placed in a specific
+    event loop of \a context. It returns a handle to the connection.
 
     This method is provided for convenience. It's equivalent to calling
-    \c {QObject::connect(timer, &QTimer::timeout, context, functor, connectionType)}.
-
-    \sa QObject::connect(), timeout()
-*/
-
-/*!
-    \fn template<typename PointerToMemberFunction> QMetaObject::Connection callOnTimeout(QObject *receiver, PointerToMemberFunction method, Qt::ConnectionType connectionType = Qt::AutoConnection)
-    \since 5.12
-    \overload callOnTimeout()
-
-    Creates a connection from the timeout() signal to the \a method in the \a receiver object. Returns
-    a handle to the connection.
-
-    This method is provided for convenience. It's equivalent to calling
-    \c {QObject::connect(timer, &QTimer::timeout, receiver, method, connectionType)}.
+    \c {QObject::connect(timer, &QTimer::timeout, context, function, connectionType)}.
 
     \sa QObject::connect(), timeout()
 */

src/corelib/kernel/qtimer.h

@@ -100,8 +100,6 @@ public:
     QMetaObject::Connection callOnTimeout(Functor slot, Qt::ConnectionType connectionType = Qt::AutoConnection);
     template <typename Functor>
     QMetaObject::Connection callOnTimeout(const QObject *context, Functor slot, Qt::ConnectionType connectionType = Qt::AutoConnection);
-    template <typename PointerToMemberFunction>
-    QMetaObject::Connection callOnTimeout(const QObject *receiver, PointerToMemberFunction slot, Qt::ConnectionType connectionType = Qt::AutoConnection);
 #else
     // singleShot to a QObject slot
     template <typename Duration, typename Func1>