Note what defer.resolve and defer.reject do. Closes gh-693

[kswedberg]

Added brief description of defer.resolve and defer.reject. @AurelioDeRosa , do you think this should cover gh-693?

[AurelioDeRosa]

The added sentence is fine and the PR looks good. I also think it covers gh-693.

I'd also take the chance to slightly clarify the sentence

If the promise already exists, however, the callback is attached to the existing deferred.

We have two cases in the code:

1. The promise didn't exist
2. The promise existed

In the first case, the promise is created (in the body of if ( !cachedScriptPromises[ url ] ) {...}) and then the callback is added. In the second case, the body of the if is skipped but the callback is added anyway. So, what about something like

If the promise already exists, the callback is attached to the existing deferred; otherwise the promise is firstly created and then the callback is attached.

[kswedberg]

@AurelioDeRosa , yeah I like your change. Thanks! I'll update the PR.

[kswedberg]

All good now?

[AurelioDeRosa]

LGTM

[kswedberg]

Closed by d08015a