instance method visit_tr

# File actiontext/lib/action_text/markdown_conversion.rb, line 237
      def visit_tr(node, child_values)
        # lexxy does not emit `thead`, so we need to infer header rows from `tr` contents
        if node.element_children.all? { |cell| cell.name == "th" }
          visit__table_header_row(node, child_values)
        else
          cells = child_values_for_elements(node, child_values).map { |v| stringify(v).strip }
          "| #{cells.join(" | ")} |\n"
        end
      end