corrected typo and improved documentation

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@8979 2fb0f335-1f38-0410-981e-8018bf24f1b0

dumux/freeflow/stokes/stokesfluxvariables.hh

@@ -355,6 +355,6 @@ protected:
     int faceIdx_;
 };
 
-} // end namepace
+} // end namespace
 
 #endif

dumux/material/fluidstates/compositionalfluidstate.hh

@@ -99,7 +99,7 @@ public:
     /*!
      * \brief The average molar mass of a fluid phase [kg/mol]
      *
-     * The average mass is the mean molar mass of a molecule of the
+     * The average molar mass is the mean mass of a mole of the
      * fluid at current composition. It is defined as the sum of the
      * component's molar masses weighted by the current mole fraction:
      * \f[ \bar M_\alpha = \sum_\kappa M^\kappa x_\alpha^\kappa \f]
@@ -264,7 +264,9 @@ public:
     { saturation_[phaseIdx] = value; }
 
     /*!
-     * \brief Set the mole fraction of a component in a phase []
+     * \brief Set the mole fraction of a component  in a phase []
+     *        and update the average molar mass [kg/mol] according
+     *        to the current composition of the phase
      */
     void setMoleFraction(int phaseIdx, int compIdx, Scalar value)
     {