Add USE_X_FORWARDED_HOST to example config (#1804)

Co-authored-by: Hubert Deng <[email protected]>

sentry/sentry.conf.example.py

@@ -222,6 +222,7 @@ def get_internal_network():
 # header and enable the settings below
 
 # SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', 'https')
+# USE_X_FORWARDED_HOST = True
 # SESSION_COOKIE_SECURE = True
 # CSRF_COOKIE_SECURE = True
 # SOCIAL_AUTH_REDIRECT_IS_HTTPS = True