[wpiutil] Deprecate wpi::math constants in favor of wpi::numbers (#3383)

The constants were moved from std::math to std::numbers before
ratification in C++20.

wpilibcExamples/src/main/cpp/examples/ArmSimulation/cpp/Robot.cpp

@@ -17,7 +17,7 @@
 #include <frc/system/plant/LinearSystemId.h>
 #include <units/angle.h>
 #include <units/moment_of_inertia.h>
-#include <wpi/math>
+#include <wpi/numbers>
 
 /**
  * This is a sample program to demonstrate how to use a state-space controller
@@ -35,7 +35,7 @@ class Robot : public frc::TimedRobot {
   // distance per pulse = (angle per revolution) / (pulses per revolution)
   //  = (2 * PI rads) / (4096 pulses)
   static constexpr double kArmEncoderDistPerPulse =
-      2.0 * wpi::math::pi / 4096.0;
+      2.0 * wpi::numbers::pi / 4096.0;
 
   // The arm gearbox represents a gerbox containing two Vex 775pro motors.
   frc::DCMotor m_armGearbox = frc::DCMotor::Vex775Pro(2);