Update interfaces/service-workers.idl (#12441)

Copied by https://github.com/foolip/wpt-idl-importer from:
https://github.com/tidoust/reffy-reports/blob/f14a522/whatwg/idl/service-workers.idl
diff --git a/interfaces/service-workers.idl b/interfaces/service-workers.idl
index 38d22c6..2c9cbf6 100644
--- a/interfaces/service-workers.idl
+++ b/interfaces/service-workers.idl
@@ -1,7 +1,7 @@
 // GENERATED CONTENT - DO NOT EDIT
-// Content of this file was automatically extracted from the
-// "Service Workers 1" spec.
-// See: https://w3c.github.io/ServiceWorker/v1/
+// Content was automatically extracted by Reffy into reffy-reports
+// (https://github.com/tidoust/reffy-reports)
+// Source: Service Workers 1 (https://w3c.github.io/ServiceWorker/v1/)
 
 [SecureContext, Exposed=(Window,Worker)]
 interface ServiceWorker : EventTarget {