Fixed a silly typo!

modules/juce_gui_basics/native/juce_win32_Windowing.cpp

@@ -385,7 +385,7 @@ public:
             sendDataChangeMessage();
     }
 
-    ImagePixelData:Ptr clone() override
+    ImagePixelData::Ptr clone() override
     {
         WindowsBitmapImage* im = new WindowsBitmapImage (pixelFormat, width, height, false);