cleaning doc

unsupported/Eigen/NonLinear

diff --git a/unsupported/Eigen/NonLinear b/unsupported/Eigen/NonLinear
index 8c373ad..103843b 100644
--- a/unsupported/Eigen/NonLinear
+++ b/unsupported/Eigen/NonLinear
@@ -22,7 +22,6 @@
 // License and a copy of the GNU General Public License along with
 // Eigen. If not, see <http://www.gnu.org/licenses/>.
 
-
 #ifndef EIGEN_NONLINEAR_MODULE_H
 #define EIGEN_NONLINEAR_MODULE_H
 
@@ -31,8 +30,12 @@
 namespace Eigen {
 
 /** \ingroup Unsupported_modules
-  * \defgroup Support for non linear optimization and non linear least
+  * \defgroup NonLinear Support for non linear optimization and non linear least
   * square using minpack routines.
+  *
+  * \code
+  * #include <unsupported/Eigen/NonLinear>
+  * \endcode
   */
 //@{