refactor: 💥 𝜋 replaced with π

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

@@ -690,13 +690,13 @@ constexpr Magnitude auto mag_power = _pow<Num, Den>(mag<Base>);
  * @brief  A convenient Magnitude constant for pi, which we can manipulate like a regular number.
  */
 #if defined MP_UNITS_COMP_CLANG || MP_UNITS_COMP_CLANG < 18
-inline constexpr struct pi final : mag_constant<symbol_text{u8"\U0001D70B", "pi"}> {
+inline constexpr struct pi final : mag_constant<symbol_text{u8"\u03c0", "pi"}> {
   static constexpr auto _value_ = std::numbers::pi_v<long double>;
 #else
-inline constexpr struct pi final : mag_constant<symbol_text{u8"\U0001D70B", "pi"}, std::numbers::pi_v<long double>> {
+inline constexpr struct pi final : mag_constant<symbol_text{u8"\u03c0", "pi"}, std::numbers::pi_v<long double>> {
 #endif
 } pi;
-inline constexpr auto 𝜋 = pi;
+inline constexpr auto π = pi;
 
 [[deprecated("Use `mag<pi>` instead")]] inline constexpr Magnitude auto mag_pi = mag<pi>;
 

src/systems/include/mp-units/systems/angular/units.h

@@ -41,7 +41,7 @@ QUANTITY_SPEC(angle, dim_angle);
 QUANTITY_SPEC(solid_angle, pow<2>(angle));
 
 inline constexpr struct radian final : named_unit<"rad", kind_of<angle>> {} radian;
-inline constexpr struct revolution final : named_unit<"rev", mag<2> * mag<𝜋> * radian> {} revolution;
+inline constexpr struct revolution final : named_unit<"rev", mag<2> * mag<π> * radian> {} revolution;
 inline constexpr struct degree final : named_unit<symbol_text{u8"°", "deg"}, mag_ratio<1, 360> * revolution> {} degree;
 inline constexpr struct gradian final : named_unit<symbol_text{u8"ᵍ", "grad"}, mag_ratio<1, 400> * revolution> {} gradian;
 inline constexpr struct steradian final : named_unit<"sr", square(radian)> {} steradian;

src/systems/include/mp-units/systems/si/constants.h

@@ -57,7 +57,7 @@ inline constexpr struct luminous_efficacy final :
 inline constexpr struct standard_gravity final :
   named_unit<symbol_text{u8"g₀", "g_0"}, mag_ratio<980'665, 100'000> * metre / square(second)> {} standard_gravity;
 inline constexpr struct magnetic_constant final :
-  named_unit<symbol_text{u8"μ₀", "u_0"}, mag<4> * mag<𝜋> * mag_power<10, -7> * henry / metre> {} magnetic_constant;
+  named_unit<symbol_text{u8"μ₀", "u_0"}, mag<4> * mag<π> * mag_power<10, -7> * henry / metre> {} magnetic_constant;
 // clang-format on
 
 }  // namespace mp_units::si

src/systems/include/mp-units/systems/si/units.h

@@ -100,7 +100,7 @@ inline constexpr struct minute final : named_unit<"min", mag<60> * si::second> {
 inline constexpr struct hour final : named_unit<"h", mag<60> * minute> {} hour;
 inline constexpr struct day final : named_unit<"d", mag<24> * hour> {} day;
 inline constexpr struct astronomical_unit final : named_unit<"au", mag<149'597'870'700> * si::metre> {} astronomical_unit;
-inline constexpr struct degree final : named_unit<symbol_text{u8"°", "deg"}, mag<𝜋> / mag<180> * si::radian> {} degree;
+inline constexpr struct degree final : named_unit<symbol_text{u8"°", "deg"}, mag<π> / mag<180> * si::radian> {} degree;
 inline constexpr struct arcminute final : named_unit<symbol_text{u8"′", "'"}, mag_ratio<1, 60> * degree> {} arcminute;
 inline constexpr struct arcsecond final : named_unit<symbol_text{u8"″", "''"}, mag_ratio<1, 60> * arcminute> {} arcsecond;
 inline constexpr struct are final : named_unit<"a", square(si::deca<si::metre>)> {} are;