Disallow periodic sync registrations from the background.

[mugdhalakhani]

This also updates some links to address the linking errors bikeshed emits after being updated.

@beverloo @jakearchibald PTAL.

[mugdhalakhani]

It's unfortunate that link-defauls keeps growing, even for something in WebIDL. Do we really need that?

The WebIDL reference has replaced a reference to promises-guide. So there's no net increase in link defaults because of that. I've tried running bikeshed using curl to rule out any staleness in my local bikeshed references, which means that these additions are indeed necessary to disambiguate between two references of the same name.

Without the 'resolve' default-link, I see this error:

Arbitrarily chose https://w3c.github.io/FileAPI/#blob-url-resolve To auto-select one of the following refs, insert one of these lines into a \

 block:
spec:webidl; type:dfn; text:resolve
spec:fileapi-1; type:dfn; text:resolve

and without the "service worker" default-link, I see this error:

Arbitrarily chose https://w3c.github.io/ServiceWorker/#dfn-service-worker To auto-select one of the following refs, insert one of these lines into a \

 block:
spec:service-workers; type:dfn; for:ServiceWorkerGlobalScope; text:service worker
spec:service-workers; type:dfn; for:/; text:service worker

Why do you think link-defaults are bad? I understand the concerns around adding to bikeshed anchors, but I'd like to understand your hesitation around adding to link-defaults. Happy to try another recommended way to disambiguate here. :)

[mugdhalakhani]

Thanks Peter. I'll ask around to see if there's a way around disambiguating with link defaults.