[documentation] adapt lambda description

MBsysC/mbs_common/mbs_struct/mbs_data.h

@@ -184,7 +184,7 @@ struct MbsData
     int Ncons;      ///< Number of algebraic constraints.
     int Nuserc;     ///< Number of user constraints.
     double NRerr;   ///< Maximal error on constraint allowed in Newton-Raphson algorithm.
-    double *lambda; ///< Array with the values of Lagrange Multiplied related to the constraints.
+    double *lambda; ///< Array with the values of the Lagrange Multipliers related to the constraints.
 	// Driven variables (and joint forces)
 	double *Qc;     ///< Array with the value of joint force introduced in driven joint to respect the user function.
                     ///< The driven forces/torques are saved in the entries given by index vector, MbsData::qc