Added the "named_deduced_unit" type and more units to the fps system

The named_deduced_unit type can be used as a named type for child for child
deduced units

src/include/units/unit.h

@@ -165,6 +165,29 @@ struct deduced_unit : downcast_child<Child, detail::deduced_unit<Dim, U, URest..
   using prefix_family = no_prefix;
 };
 
+
+/**
+ * @brief A unit with a deduced ratio and symbol that can be used as a named unit for children 
+ *
+ * Defines a new unit with a deduced ratio and symbol based on the recipe from the provided
+ * derived dimension. The number and order of provided units should match the recipe of the
+ * derived dimension. All of the units provided should also be a named ones so it is possible
+ * to create a deduced symbol text.
+ *
+ * @tparam Child inherited class type used by the downcasting facility (CRTP Idiom)
+ * @tparam Dim a derived dimension recipe to use for deduction
+ * @tparam U the unit of the first composite dimension from provided derived dimension's recipe
+ * @tparam URest the units for the rest of dimensions from the recipe
+ */
+template<typename Child, DerivedDimension Dim, Unit U, Unit... URest>
+  requires detail::same_scaled_units<typename Dim::recipe, U, URest...> &&
+           (U::is_named && (URest::is_named && ... && true))
+struct named_deduced_unit : downcast_child<Child, detail::deduced_unit<Dim, U, URest...>> {
+  static constexpr bool is_named = true;
+  static constexpr auto symbol = detail::deduced_symbol_text<Dim, U, URest...>();
+  using prefix_family = no_prefix;
+};
+
 // template<typename Child, Dimension Dim, basic_fixed_string Symbol, PrefixFamily PF, Unit U, Unit... Us>
 // struct named_deduced_derived_unit : downcast_child<Child, detail::deduced_derived_unit<Dim, U, Us...>> {
 //   static constexpr bool is_named = true;