[plugin] HTTPInspector: return InputEvent on every call to reset standby/suspend timer (#13339)

Fixes #13303.

frontend/ui/message/simpletcpserver.lua

@@ -50,7 +50,7 @@ function SimpleTCPServer:waitEvent()
                 logger.dbg("SimpleTCPServer: Received data: ", data)
                 -- Give us more time to process the request and send the response
                 client:settimeout(0.5, "t")
-                self.receiveCallback(data, client)
+                return self.receiveCallback(data, client)
                     -- This should call SimpleTCPServer:send() to send
                     -- the response and close this connection.
             else

plugins/httpinspector.koplugin/main.lua

@@ -290,6 +290,7 @@ function HttpInspector:sendResponse(reqinfo, http_code, content_type, body)
     if self.http_socket then -- in case the plugin is gone...
         self.http_socket:send(response, reqinfo.request_id)
     end
+    return Event:new("InputEvent") -- as a key event, reset any standby/suspend timer
 end
 
 -- Process a uri, stepping one fragment (consider ? / = as separators)