[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/GyroDriveCommands/include/Constants.h

@@ -6,7 +6,7 @@
 
 #include <units/angle.h>
 #include <units/angular_velocity.h>
-#include <wpi/math>
+#include <wpi/numbers>
 
 /**
  * The Constants header provides a convenient place for teams to hold robot-wide
@@ -32,7 +32,8 @@ constexpr int kEncoderCPR = 1024;
 constexpr double kWheelDiameterInches = 6;
 constexpr double kEncoderDistancePerPulse =
     // Assumes the encoders are directly mounted on the wheel shafts
-    (kWheelDiameterInches * wpi::math::pi) / static_cast<double>(kEncoderCPR);
+    (kWheelDiameterInches * wpi::numbers::pi) /
+    static_cast<double>(kEncoderCPR);
 
 constexpr bool kGyroReversed = true;