Put the comment back.

Former-commit-id: 7fac7605f445d5b143677c64d7ca333dce684439

include/igl/copyleft/cgal/assign_scalar.cpp

@@ -18,6 +18,7 @@ IGL_INLINE void igl::copyleft::cgal::assign_scalar(
   const typename CGAL::Epeck::FT & _cgal,
   double & d)
 {
+  // FORCE evaluation of the exact type otherwise interval might be huge.
   const typename CGAL::Epeck::FT cgal = _cgal.exact();
   const auto interval = CGAL::to_interval(cgal);
   d = interval.first;
@@ -32,6 +33,7 @@ IGL_INLINE void igl::copyleft::cgal::assign_scalar(
   const typename CGAL::Epeck::FT & _cgal,
   float& d)
 {
+  // FORCE evaluation of the exact type otherwise interval might be huge.
   const typename CGAL::Epeck::FT cgal = _cgal.exact();
   const auto interval = CGAL::to_interval(cgal);
   d = interval.first;