Updates docs on new client IP with x-forwarded-for

Signed-off-by: JoshVanL <[email protected]>

Author: JoshVanL

docs/tasks/extra-impersonation-headers.md

@@ -15,7 +15,9 @@ extra header:
 Proxied requests will then contain the header
 `Impersonate-Extra-Remote-Client-Ip: <REMOTE_ADDR>` where  `<REMOTE_ADDR>` is
 the address of the source connection of the request. Note that this IP address
-may not be the real client IP address when the request is being proxied.
+may not be the real client IP address when the request is being proxied. If the
+`X-Forwarded-For` header is present in the request then the value will be used
+as the client address.
 
 # Extra User Headers