Update "Namespace Isolation" pattern description

[ericcornelissen]

Relates to #10

[ericcornelissen]

Also, some newer <iframe>-based clobbering techniques might be able to sidestep it.

Am I correct in understanding this applies to both the MutationObserver-based approach as well as DOMPurify? I haven't currently written it this way in the PR because I haven't tried the DOMPurify solution.

[SoheilKhodayari]

Am I correct in understanding this applies to both the MutationObserver-based approach as well as DOMPurify? I haven't currently written it this way in the PR because I haven't tried the DOMPurify solution.

I think It only affects the MutationObserver-based approach, because the parent page cannot monitor the DOM of the framed pages. DOMPurify can see and remove the id and name attributes of such clobbering markups before they are injected to the DOM.