better documentation

Former-commit-id: 0197ed5910c65a7391455b10445d7fe5590f724d

include/igl/eigs.h

@@ -27,12 +27,12 @@ namespace igl
   //   A  #A by #A symmetric matrix
   //   B  #A by #A symmetric positive-definite matrix
   //   k  number of eigen pairs to compute
+  //   type  whether to extract from the high or low end
   // Outputs:
   //   sU  #A by k list of sorted eigen vectors (descending)
   //   sS  k list of sorted eigen values (descending)
   //
   // Known issues:
-  //   - only one pair per eigen value is found (no multiples)
   //   - only the 'sm' small magnitude eigen values are well supported
   //   
   enum EigsType