Drop custom reference for WorkerGlobalScope (#148)

Web Workers are no long being worked upon in W3C. Reference needs to be to
the HTML LS spec. Bikeshed does the right thing on its own, we just need to
stay out of the way...

Requested for publication to First Public Working Draft:
w3c/transitions#213 (comment)

index.bs

@@ -98,9 +98,6 @@ spec: encrypted-media-draft; for: EME; urlPrefix: https://w3c.github.io/encrypte
 
 spec: secure-contexts; urlPrefix: https://www.w3.org/TR/secure-contexts/
     type: dfn; text: Is the environment settings object settings a secure context?; url: #settings-object
-
-spec: workers; urlPrefix: https://www.w3.org/TR/workers/#
-    type: interface; text: WorkerGlobalScope; url: the-workerglobalscope-common-interface
 </pre>
 
 <pre class='biblio'>