[!553] [bugfix] allow single argument `range(...)` with enum values

Merge branch 'feature/range-with-enums' into 'master'

Fixes the defect of the single argument range(...) that enum values could not
be used without casting. I would like to see this being backported to 2.6.

See merge request [core/dune-common!553]

  [core/dune-common!553]: gitlab.dune-project.org/core/dune-common/merge_requests/553

dune/common/rangeutilities.hh

@@ -286,6 +286,12 @@ namespace Dune
     return IntegralRange<std::decay_t<T>>(std::forward<T>(to));
   }
 
+  template<class T, std::enable_if_t<std::is_enum<std::decay_t<T>>::value, int> = 0>
+  inline static IntegralRange<std::underlying_type_t<std::decay_t<T>>> range(T &&to) noexcept
+  {
+    return IntegralRange<std::underlying_type_t<std::decay_t<T>>>(std::forward<T>(to));
+  }
+
   template<class T, T from, T to>
   inline static StaticIntegralRange<T, to, from> range(std::integral_constant<T, from>, std::integral_constant<T, to>) noexcept
   {