code: public Quaterniond rotationAxis(AxisAngle4f axisAngle) {
          return rotationAxis(axisAngle.angle, axisAngle.x, axisAngle.y, axisAngle.z);
      }
docs: Set this {@link Quaterniond} to a rotation of the given angle in radians about the supplied
  axis, all of which are specified via the {@link AxisAngle4f}.
  
  @see #rotationAxis(double, double, double, double)
  
  @param axisAngle
  the {@link AxisAngle4f} giving the rotation angle in radians and the axis to rotate about
  @return this