message: Fixing documentation for new argument name
diff: @@ -237,7 +237,7 @@ public:
  //! Add block op in the block-entry (iblock, iblock).
  /**
  * @param iblock The block will be inserted in location (iblock, iblock).
  - * @param op The Operator to be inserted.
  + * @param opt The Operator to be inserted.
  */
  void SetDiagonalBlock(int iblock, Operator *opt);
  //! Add a block opt in the block-entry (iblock, jblock).
  