consolidating dot visitor methods

lib/arel/visitors/dot.rb

@@ -28,10 +28,6 @@ def accept object
       end
 
       private
-      def visit_Arel_Nodes_Grouping o
-        visit_edge o, "expr"
-      end
-
       def visit_Arel_Nodes_Ordering o
         visit_edge o, "expr"
         visit_edge o, "direction"
@@ -55,10 +51,6 @@ def visit_Arel_Nodes_Count o
         visit_edge o, "distinct"
       end
 
-      def visit_Arel_Nodes_On o
-        visit_edge o, "expr"
-      end
-
       def visit_Arel_Nodes_Values o
         visit_edge o, "expressions"
       end
@@ -80,10 +72,6 @@ def visit_Arel_Nodes_DeleteStatement o
         visit_edge o, "wheres"
       end
 
-      def visit_Arel_Nodes_UnqualifiedColumn o
-        visit_edge o, "attribute"
-      end
-
       def unary o
         visit_edge o, "expr"
       end