Mistake in interactive documentation page

[turbcool]

There is a mistake in code on the interactive documentation page.

application.inject(injectionTarget, 'notifications', 'notification-messages:service')

'notification-messages:service' should be 'service:notifications'

[jacobq]

Ha, just saw this (after mentioning in #311), but you are right. In fact, now in Ember 4.x injecting like that no longer works, so I've suggested removing this part of the docs in #339