[push-api] Have PermissionDeniedError added to WebIDL (#186)

https://w3c.github.io/push-api/#exceptions

This should ideally be in http://heycam.github.io/webidl/#dfn-error-names-table so that other specifications can use it. Please file an issue at https://github.com/heycam/webidl/issues if you agree.

Note that `NotAllowedError` was added in https://github.com/heycam/webidl/pull/85 and this is very similar. It might not make sense to keep both, which would be resolved by trying to get both into the same spec :)

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/push-api/issues/186