message: Update the comment for DataCollection::Format to clarify that derived
  classes can define their own format enumerations.
  [skip ci]
diff: @@ -33,6 +33,8 @@ public:
  typedef std::map<std::string, QuadratureFunction*> QFieldMapType;
  /// Format constants to be used with SetFormat().
  + /** Derived classes can define their own format enumerations and override the
  + method SetFormat() to perform input validation. */
  enum Format
  {
  SERIAL_FORMAT = 0, /**<
  