#859 Improve a comment following a question from Patrick Le Tallec which...

#859 Improve a comment following a question from Patrick Le Tallec which answer was not clear due to insufficient comment.

Sources/Operators/GlobalVariationalOperator/ExtractLocalDofValues.hpp

@@ -53,7 +53,8 @@ namespace MoReFEM
          * to global array must have been computed for this unknown.
          * \param[in] vector Global vector from which we seek to extract relevant local values.
          * \param[out] result Vector into which result of the function is written. This vector is assumed to be properly
-         * allocated before the call to this function.
+         * allocated before the call to this function. This vector follows the ordering convention of local vectors
+         * (i.e. dofs are grouped by component: vx1 vx2 vx3 vy1 vy2 vy3...)
          */
         void ExtractLocalDofValues(const LocalFEltSpace& local_felt_space,
                                    const ExtendedUnknown& unknown,