wxQt: Make wxEventLoop::Pending() return false unconditionally and document that

Because implementing this function reliably in wxQt is difficult, if not possible.

interface/wx/evtloop.h

@@ -133,6 +133,8 @@ public:
         Return true if any events are available.
 
         If this method returns @true, calling Dispatch() will not block.
+
+        @note This function always returns @false under wxQt since 3.3.0
      */
     virtual bool Pending() const = 0;
 

src/qt/evtloop.cpp

@@ -126,8 +126,15 @@ int wxQtEventLoopBase::DoRun()
 
 bool wxQtEventLoopBase::Pending() const
 {
-    QAbstractEventDispatcher *instance = QAbstractEventDispatcher::instance();
-    return instance->hasPendingEvents();
+    // Note that we are not using any of the QAbstractEventDispatcher::hasPendingEvents()
+    // or QCoreApplication::hasPendingEvents() functions here to check for pending events,
+    // as the functions were deprecated in Qt5.3 and removed entirely in Qt6 due to their
+    // unreliable way to check for pending events according to the Qt developers.
+    //
+    // So, in the absence of a replacement for these functions, this function is useless
+    // under wxQt as it just returns false.
+
+    return false;
 }
 
 bool wxQtEventLoopBase::Dispatch()