oops, promises must return errors, not throw them

index.bs

@@ -2541,7 +2541,7 @@ to successfully invoke the [=Web Authentication API=], i.e., via
 <code><a idl for="CredentialsContainer" lt="create()">navigator.credentials.create({publicKey:..., ...})</a></code> and
 <code><a idl for="CredentialsContainer" lt="get()">navigator.credentials.get({publicKey:..., ...})</a></code>.
 If disabled in any document, no content in the document will be [=allowed to use=]
-the foregoing methods: attempting to do so will throw an error.
+the foregoing methods: attempting to do so will [return an error](https://www.w3.org/2001/tag/doc/promises-guide#errors).
 
 Note: Algorithms specified in [[!CREDENTIAL-MANAGEMENT-1]] perform the actual feature policy evaluation. This is because such policy evaluation needs to occur when there is access to the [=current settings object=]. The {{PublicKeyCredential/[[Create]](origin, options, sameOriginWithAncestors)}} and {{PublicKeyCredential/[[DiscoverFromExternalSource]](origin, options, sameOriginWithAncestors)}} [=internal methods=] do not have such access since they are invoked [=in parallel=] (by algorithms specified in [[!CREDENTIAL-MANAGEMENT-1]]).