Fix Doxygen bug with Singleton macros

modules/juce_analytics/analytics/juce_Analytics.h

@@ -79,8 +79,9 @@ public:
     */
     void setSuspended (bool shouldBeSuspended);
 
-
+   #ifndef DOXYGEN
     juce_DeclareSingleton (Analytics, true)
+   #endif
 
 private:
     //==============================================================================

modules/juce_gui_basics/components/juce_ModalComponentManager.h

@@ -74,7 +74,9 @@ public:
     };
 
     //==============================================================================
+   #ifndef DOXYGEN
     juce_DeclareSingleton_SingleThreaded_Minimal (ModalComponentManager)
+   #endif
 
     //==============================================================================
     /** Returns the number of components currently being shown modally.

modules/juce_gui_extra/misc/juce_PushNotifications.h

@@ -44,7 +44,9 @@ namespace juce
 class JUCE_API PushNotifications
 {
 public:
+   #ifndef DOXYGEN
     juce_DeclareSingleton (PushNotifications, false)
+   #endif
 
     //==========================================================================
     /** Represents a notification that can be sent or received. */