Add documentation for camera path instruction dictionary

used as input for `openspace.pathnavigation.createPath`

include/openspace/navigation/path.h

@@ -25,6 +25,7 @@
 #ifndef __OPENSPACE_CORE___PATH___H__
 #define __OPENSPACE_CORE___PATH___H__
 
+#include <openspace/documentation/documentation.h>
 #include <openspace/navigation/pathcurve.h>
 #include <openspace/navigation/waypoint.h>
 #include <ghoul/misc/dictionary.h>
@@ -110,6 +111,8 @@ public:
      */
     void resetPlaybackVariables();
 
+    static documentation::Documentation Documentation();
+
 private:
     /**
      * Interpolate between the paths start and end rotation using the approach that