Update http.md

docs/en/interfaces/http.md

@@ -426,6 +426,9 @@ Next are the configuration methods for different `type`.
 
 The following example defines the values of [max_threads](../operations/settings/settings.md#settings-max_threads) and `max_alter_threads` settings, then queries the system table to check whether these settings were set successfully.
 
+!!! note "Warning"
+    To keep the default `handlers` such as` query`, `play`,` ping`, use the `<defaults/>` rule. 
+
 Example:
 
 ``` xml
@@ -443,6 +446,7 @@ Example:
             <query>SELECT name, value FROM system.settings WHERE name = {name_2:String}</query>
         </handler>
     </rule>
+    <defaults/>
 </http_handlers>
 ```
 
@@ -475,6 +479,7 @@ Example:
         <query_param_name>query_param</query_param_name>
     </handler>
     </rule>
+    <defaults/>
 </http_handlers>
 ```
 
@@ -505,6 +510,7 @@ Return a message.
                 <response_content>Say Hi!</response_content>
             </handler>
         </rule>
+        <defaults/>
 </http_handlers>
 ```