refactor: physical replaced with isq

Refers to #249

docs/use_cases/extensions.rst

@@ -57,7 +57,7 @@ Enabling a Unit for Prefixing
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 In case I decide it is reasonable to express my desks with SI prefixes the only thing I have
-to change in the above code is to replace `no_prefix` with `physical::si::prefix`::
+to change in the above code is to replace `no_prefix` with `isq::si::prefix`::
 
     struct desk : named_scaled_unit<desk, "desk", si::prefix, ratio(3, 10), si::square_metre> {};
 
@@ -231,8 +231,8 @@ different systems:
 
     namespace si {
 
-    struct metre : named_unit<metre, "m", units::physical::si::prefix> {};
-    struct kilometre : prefixed_unit<kilometre, units::physical::si::kilo, metre> {};
+    struct metre : named_unit<metre, "m", units::isq::si::prefix> {};
+    struct kilometre : prefixed_unit<kilometre, units::isq::si::kilo, metre> {};
 
     struct dim_length : base_dimension<"L", metre> {};
 

docs/use_cases/interoperability.rst

@@ -16,14 +16,14 @@ provide the following:
 For example, to provide support for the ``std::chrono::duration`` it is enough to define::
 
     #include <units/customization_points.h>
-    #include <units/physical/si/time.h>
+    #include <units/isq/si/time.h>
     #include <chrono>
 
     namespace units {
 
     template<typename Rep, typename Period>
     struct quantity_like_traits<std::chrono::duration<Rep, Period>> {
-      using dimension = physical::si::dim_time;
+      using dimension = isq::si::dim_time;
       using unit = downcast_unit<dimension, ratio(Period::num, Period::den)>;
       using rep = Rep;
       [[nodiscard]] static constexpr rep count(const std::chrono::duration<Rep, Period>& q) { return q.count(); }

docs/use_cases/legacy_interfaces.rst

@@ -25,10 +25,10 @@ and pass it to the library's output:
 .. code-block::
 
     #include "legacy.h"
-    #include <units/physical/si/si.h>
+    #include <units/isq/si/si.h>
     #include <units/quantity_point.h>
 
-    using namespace units::physical;
+    using namespace units::isq;
 
     constexpr Speed auto avg_speed(Length auto d, Time auto t)
     {

docs/use_cases/unknown_dimensions.rst

@@ -22,9 +22,9 @@ The same applies to the resulting unit. For example:
 .. code-block::
     :emphasize-lines: 1,7,9
 
-    #include <units/physical/si/si.h>
+    #include <units/isq/si/si.h>
 
-    using namespace units::physical::si;
+    using namespace units::isq::si;
 
     constexpr auto result = 144_q_km / 2_q_h;
     static_assert(std::is_same_v<decltype(result)::dimension,
@@ -41,10 +41,10 @@ dimensions used in the division operation:
 .. code-block::
     :emphasize-lines: 1-2,8,10
 
-    #include <units/physical/si/length.h>
-    #include <units/physical/si/time.h>
+    #include <units/isq/si/length.h>
+    #include <units/isq/si/time.h>
 
-    using namespace units::physical::si;
+    using namespace units::isq::si;
 
     constexpr auto result = 144_q_km / 2_q_h;
     static_assert(std::is_same_v<decltype(result)::dimension,
@@ -55,7 +55,7 @@ dimensions used in the division operation:
 .. important::
 
     To limit the possibility of an ODR violation please always include a header file
-    with all the definitions for the current system (e.g. *units/physical/si/si.h*).
+    with all the definitions for the current system (e.g. *units/isq/si/si.h*).
 
 
 Operations On Unknown Dimensions And Their Units