[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/java/edu/wpi/first/math/geometry/Translation2d.java

@@ -97,6 +97,15 @@ public class Translation2d implements Interpolatable<Translation2d> {
     return Math.hypot(m_x, m_y);
   }
 
+  /**
+   * Returns the angle this translation forms with the positive X axis.
+   *
+   * @return The angle of the translation
+   */
+  public Rotation2d getAngle() {
+    return new Rotation2d(m_x, m_y);
+  }
+
   /**
    * Applies a rotation to the translation in 2D space.
    *