[wpimath] Revert Rotation2D change that limits angles (#4781)

Reverts "[wpimath] Constrain Rotation2d range to -pi to pi (#4611)"
This reverts commit d1d458db2b.

This broke multiple teams code in beta. It is also easier to limit the angle externally, then reconstruct a larger angle that got limited. This additionally adds comments to clarify the behavior and retains tests that were added in the reverted commit, and fixes a javadoc comment angle reference.

wpilibj/src/main/java/edu/wpi/first/wpilibj/interfaces/Gyro.java

@@ -52,6 +52,10 @@ public interface Gyro extends AutoCloseable {
   /**
    * Return the heading of the robot as a {@link edu.wpi.first.math.geometry.Rotation2d}.
    *
+   * <p>The angle is continuous, that is it will continue from 360 to 361 degrees. This allows
+   * algorithms that wouldn't want to see a discontinuity in the gyro output as it sweeps past from
+   * 360 to 0 on the second time around.
+   *
    * <p>The angle is expected to increase as the gyro turns counterclockwise when looked at from the
    * top. It needs to follow the NWU axis convention.
    *