[wpimath] Add Translation2d.getAngle() (#4217)

Co-authored-by: Max Gordon <tonald.drump2.0@gamil.com>
Co-authored-by: Tyler Veness <calcmogul@gmail.com>

wpimath/src/main/native/include/frc/geometry/Translation2d.h

@@ -80,6 +80,13 @@ class WPILIB_DLLEXPORT Translation2d {
    */
   units::meter_t Norm() const;
 
+  /**
+   * Returns the angle this translation forms with the positive X axis.
+   *
+   * @return The angle of the translation
+   */
+  Rotation2d Angle() const;
+
   /**
    * Applies a rotation to the translation in 2D space.
    *