Update generic-class.rst (#5338)

Fix link to WiFiEvents
Add note about WiFiClients and WiFiServers going down when a WiFi interface goes down, and that it's the user's responsibility to bring them back up.

Author: devyte

doc/esp8266wifi/generic-class.rst

@@ -12,7 +12,6 @@ onEvent
 
     void  onEvent (WiFiEventCb cb, WiFiEvent_t event=WIFI_EVENT_ANY) __attribute__((deprecated))
 
-To see how to use ``onEvent`` please check example sketch `WiFiClientEvents.ino <https://github.com/esp8266/Arduino/blob/master/libraries/ESP8266WiFi/examples/WiFiClientEvents/WiFiClientEvents.ino>`__ available inside examples folder of the ESP8266WiFi library.
 
 WiFiEventHandler
 ~~~~~~~~~~~~~~~~
@@ -27,7 +26,14 @@ WiFiEventHandler
     WiFiEventHandler  onSoftAPModeStationConnected (std::function< void(const WiFiEventSoftAPModeStationConnected &)>)
     WiFiEventHandler  onSoftAPModeStationDisconnected (std::function< void(const WiFiEventSoftAPModeStationDisconnected &)>)
 
-To see a sample application with ``WiFiEventHandler``, please check separate section with `examples :arrow\_right: <generic-examples.rst>`__ dedicated specifically to the Generic Class..
+It should be noted that when an WiFi interface goes down, all WiFiClients are stopped, and all WiFiServers stop serving. When the interface comes up, it is up to the user to reconnect the relevant WiFiClients and bring the WiFiServers back up. 
+For the WiFi station interface, it is suggested to set a callback for onStationModeDisconnected() that shuts down the user app's WiFiClients and WiFiServers (resource cleanup), and another callback for onStationModeGotIP() that brings them back up.
+For the SoftAP interface, when the interface is brought up, any servers should be brought up as well.
+
+A detailed explanation of ``WiFiEventHandler`` can be found in the section with `examples :arrow\_right: <generic-examples.rst>`__ dedicated specifically to the Generic Class..
+
+Alternatively, check the example sketch `WiFiEvents.ino <https://github.com/esp8266/Arduino/blob/master/libraries/ESP8266WiFi/examples/WiFiEvents/WiFiEvents.ino>`__ available inside examples folder of the ESP8266WiFi library.
+
 
 persistent
 ~~~~~~~~~~