improvement on reply function.

message.go

@@ -122,9 +122,7 @@ func (m Message) Reply(mention bool, sm *SendMessage) (*Message, error) {
 		sm.CreateNonce()
 	}
 
-	if len(sm.Content) < 1968 && mention {
-		sm.Content = "<@" + m.AuthorId + ">, " + sm.Content
-	}
+	sm.AddReply(m.Id, mention)
 
 	respMessage := &Message{}
 	respMessage.Client = m.Client

other.go

@@ -1,5 +1,7 @@
 package revoltgo
 
+import "fmt"
+
 // Similar to message, but created for send message function.
 type SendMessage struct {
 	Content     string   `json:"content,omitempty"`
@@ -17,6 +19,12 @@ func (sms *SendMessage) SetContent(content string) *SendMessage {
 	return sms
 }
 
+// Set and format content.
+func (sms *SendMessage) SetContentf(format string, values ...interface{}) *SendMessage {
+	sms.Content = fmt.Sprintf(format, values...)
+	return sms
+}
+
 // Add a new attachment.
 func (sms *SendMessage) AddAttachment(attachment string) *SendMessage {
 	sms.Attachments = append(sms.Attachments, attachment)