code: public TableBuilder addHeaderBorder(BorderStyle style) {
  		this.addBorder(0, 0, 1, model.getColumnCount(), OUTLINE, style);
  		return addOutlineBorder(style);
  	}
docs: Set a border on the outline of the whole table, as well as around the first row.
  @param style the style to apply
  @return this, for method chaining