Add note about Windows Defender (#47298)

https://twitter.com/timneutkens/status/1637504870541320193

Author: leerob

docs/advanced-features/debugging.md

@@ -97,6 +97,8 @@ Windows users may run into an issue when using `NODE_OPTIONS='--inspect'` as tha
 
 `cross-env` will set the `NODE_OPTIONS` environment variable regardless of which platform you are on (including Mac, Linux, and Windows) and allow you to debug consistently across devices and operating systems.
 
+> **Note:** Ensure Windows Defender is disabled on your machine. This external service will check _every file read_, which has been reported to greatly increase Fast Refresh time with `next dev`. This is a known issue, not related to Next.js, but it does affect Next.js development.
+
 ## More information
 
 To learn more about how to use a JavaScript debugger, take a look at the following documentation: