Update as-api-listener.md

docs/software-developer-documentation/server-side-extensions/as-api-listener.md

@@ -58,9 +58,7 @@ is provided with the V3 API jar and provides 3 methods:
     session token used for the operation, the operation result and any
     exception that happened during the operation.
 
-```{warning}
-Implicit Requirements
-
+```{warning} Implicit Requirements
 **Requirement 1:  The Listener should be Thread Safe Code**
 
 A single instance of the Listener is created during the server startup.