[TASK] Fixing gitlab markdown headers

README.md

@@ -133,7 +133,7 @@ With the **Mail Queue** mode, you can see the current content of your mailing qu
 To register your extension you need at least one implementation of this interface. 
 Inside the **init()** function of your Implementation you should define variables for the following purposes:
 
-######Template Key
+#####Template Key
 A unique Identifier for this particular template. It should be obvious from the template key for what purpose this template is intended.
 
 #####Extension Key