Correct swagger annotations for enums, status codes, and notification state (#37030)

## ⚠️ BREAKING ⚠️

- delete reaction endpoints is changed to return 204 No Content rather
than 200 with no content.

## Summary

Add swagger:enum annotations and migrate all enum comments from the
deprecated comma-separated format to JSON arrays. Introduce
NotifySubjectStateType with open/closed/merged values. Fix delete
reaction endpoints to return 204 instead of 200.

modules/structs/hook.go

@@ -51,7 +51,7 @@ type CreateHookOptionConfig map[string]string
 // CreateHookOption options when create a hook
 type CreateHookOption struct {
 	// required: true
-	// enum: dingtalk,discord,gitea,gogs,msteams,slack,telegram,feishu,wechatwork,packagist
+	// enum: ["dingtalk","discord","gitea","gogs","msteams","slack","telegram","feishu","wechatwork","packagist"]
 	// The type of the webhook to create
 	Type string `json:"type" binding:"Required"`
 	// required: true