chore: update "DO NOT EDIT" format (#2559)

* chore: update "DO NOT EDIT" format

* Update readme.md

* Update head.go

tools/goctl/model/mongo/readme.md

@@ -57,7 +57,7 @@ func NewUserModel(url, db, collection string, c cache.CacheConf) UserModel {
 
 #### usermodelgen.go
 ```go
-// Code generated by goctl. DO NOT EDIT!
+// Code generated by goctl. DO NOT EDIT.
 package model
 
 import (

tools/goctl/model/mongo/template/model.tpl

@@ -1,4 +1,4 @@
-// Code generated by goctl. DO NOT EDIT!
+// Code generated by goctl. DO NOT EDIT.
 package model
 
 import (

tools/goctl/util/head.go

@@ -2,7 +2,7 @@ package util
 
 const (
 	// DoNotEditHead added to the beginning of a file to prompt the user not to edit
-	DoNotEditHead = "// Code generated by goctl. DO NOT EDIT!"
+	DoNotEditHead = "// Code generated by goctl. DO NOT EDIT."
 
 	headTemplate = DoNotEditHead + `
 // Source: {{.source}}`