doc: revise agent.destroy() text

PR-URL: #36163
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Harshitha K P <harshitha014@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

doc/api/http.md

@@ -253,8 +253,8 @@ Destroy any sockets that are currently in use by the agent.
 
 It is usually not necessary to do this. However, if using an
 agent with `keepAlive` enabled, then it is best to explicitly shut down
-the agent when it will no longer be used. Otherwise,
-sockets may hang open for quite a long time before the server
+the agent when it is no longer needed. Otherwise,
+sockets might stay open for quite a long time before the server
 terminates them.
 
 ### `agent.freeSockets`