docs: Update gluUnProject parameter description.

     * @param view the current view, {x, y, width, height}

     * @param viewOffset the offset into the view array where the view vector

     *        data starts.

     * @param obj the output vector {objX, objY, objZ}, that returns the

     *        computed object coordinates.

     * @param obj the output vector {objX, objY, objZ, objW}, that returns the

     *        computed homogeneous object coordinates.

     * @param objOffset the offset into the obj array where the obj vector data

     *        starts.

     * @return A return value of GL10.GL_TRUE indicates success, a return value