Move wxBitmap::ConvertToDisabled() to respect alphabetic order

No real changes, just keep the functions sorted as they're clearly
intended to be here.

This commit is best viewed with --color-moved git option.

interface/wx/bitmap.h

@@ -402,6 +402,15 @@ public:
     */
     static void CleanUpHandlers();
 
+    /**
+        Returns disabled (dimmed) version of the bitmap.
+
+        This method is not available when <code>wxUSE_IMAGE == 0</code>.
+
+        @since 2.9.0
+    */
+    wxBitmap ConvertToDisabled(unsigned char brightness = 255) const;
+
     /**
         Creates an image from a platform-dependent bitmap. This preserves
         mask information so that bitmaps and images can be converted back
@@ -577,15 +586,6 @@ public:
     */
     wxSize GetSize() const;
 
-    /**
-        Returns disabled (dimmed) version of the bitmap.
-
-        This method is not available when <code>wxUSE_IMAGE == 0</code>.
-
-        @since 2.9.0
-    */
-    wxBitmap ConvertToDisabled(unsigned char brightness = 255) const;
-
     /**
         Gets the width of the bitmap in pixels.