entc/gen: add type for type edges (#318)

Will be used for adding methods on the struct edges

examples/m2mbidi/ent/user.go

@@ -25,10 +25,13 @@ type User struct {
 	Name string `json:"name,omitempty"`
 	// Edges holds the relations/edges for other nodes in the graph.
 	// The values are being populated by the UserQuery when eager-loading is set.
-	Edges struct {
-		// Friends holds the value of the friends edge.
-		Friends []*User
-	} `json:"edges"`
+	Edges UserEdges `json:"edges"`
+}
+
+// UserEdges holds the relations/edges for other nodes in the graph.
+type UserEdges struct {
+	// Friends holds the value of the friends edge.
+	Friends []*User
 }
 
 // scanValues returns the types for scanning values from sql.Rows.