Update api-reference.mdx

docs/cardinal/game/world/api-reference.mdx

@@ -184,7 +184,9 @@ func TestGameSystem(t *testing.T) {
 
 <Tip>
     The WithTickDoneChannel is essential for writing deterministic tests. Always wait for the done signal before making assertions about game state changes.
-</Tip>#### WithMessageExpiration
+</Tip>
+
+#### WithMessageExpiration
 
 The `WithMessageExpiration` option controls how long messages will live past their creation time on the sender before they are considered to be expired and will not be processed. Default is 10 seconds. For longer expiration times you may also need to set a larger hash cache size using the `WithHashCacheSize` option. This setting is ignored if the DisableSignatureVerification option is used. **NOTE**: this means that the real time clock for the sender and receiver must be synchronized