Added some comments

src/modules/navigator/navigator.h

@@ -58,6 +58,10 @@
 #include "rtl.h"
 #include "geofence.h"
 
+/**
+ * Number of navigation modes that need on_active/on_inactive calls
+ * Currently: mission, loiter, and rtl
+ */
 #define NAVIGATOR_MODE_ARRAY_SIZE 3
 
 class Navigator : public control::SuperBlock