fix: std::numeric_limits usage fixed

Author: mpusz

src/core/include/mp-units/framework/customization_points.h

@@ -97,15 +97,15 @@ struct representation_values {
   }
 
   static constexpr Rep min() noexcept
-    requires requires {
+    requires std::numeric_limits<Rep>::is_specialized && requires {
       { std::numeric_limits<Rep>::lowest() } -> std::same_as<Rep>;
     }
   {
     return std::numeric_limits<Rep>::lowest();
   }
 
   static constexpr Rep max() noexcept
-    requires requires {
+    requires std::numeric_limits<Rep>::is_specialized && requires {
       { std::numeric_limits<Rep>::max() } -> std::same_as<Rep>;
     }
   {

src/core/include/mp-units/framework/quantity.h

@@ -696,7 +696,7 @@ template<mp_units::Quantity Q, mp_units::RepresentationOf<Q::quantity_spec> Valu
 struct std::common_type<Value, Q> : std::common_type<Q, Value> {};
 
 template<auto R, typename Rep>
-  requires requires { typename std::numeric_limits<Rep>; }
+  requires std::numeric_limits<Rep>::is_specialized
 class std::numeric_limits<mp_units::quantity<R, Rep>> : public std::numeric_limits<Rep> {
 public:
   static constexpr mp_units::quantity<R, Rep> min() noexcept

src/core/include/mp-units/framework/quantity_point.h

@@ -564,7 +564,7 @@ explicit(quantity_point_like_traits<QP>::explicit_import) quantity_point(QP)
 }  // namespace mp_units
 
 template<auto R, auto PO, typename Rep>
-  requires requires { typename std::numeric_limits<Rep>; }
+  requires std::numeric_limits<Rep>::is_specialized
 class std::numeric_limits<mp_units::quantity_point<R, PO, Rep>> : public std::numeric_limits<Rep> {
 public:
   static constexpr mp_units::quantity_point<R, PO, Rep> min() noexcept