mod: correct comments in header files. (#2007)

* mod: correct comments in header files.

* Update average_onto_faces.h

Co-authored-by: Alec Jacobson <[email protected]>

include/igl/average_onto_faces.h

@@ -12,8 +12,7 @@
 #include <Eigen/Dense>
 namespace igl 
 {
-  // average_onto_vertices 
-  // Move a scalar field defined on faces to vertices by averaging
+  // Move a scalar field defined on vertices to faces by averaging
   //
   // Input:
   //   F  #F by ss list of simples/faces

include/igl/signed_distance.h

@@ -74,8 +74,6 @@ namespace igl
   //   F  #F by ss list of triangle indices, ss should be 3 unless sign_type ==
   //     SIGNED_DISTANCE_TYPE_UNSIGNED
   //   sign_type  method for computing distance _sign_ S
-  //   lower_bound  lower bound of distances needed {std::numeric_limits::min}
-  //   upper_bound  lower bound of distances needed {std::numeric_limits::max}
   // Outputs:
   //   S  #P list of smallest signed distances
   //   I  #P list of facet indices corresponding to smallest distances