The special behaviour or Enter should be always enabled

[Reinmar]

Right now we check whether the enter command exists. If, however, the heading feature was loaded first, this is not going to work.

I noticed this issue because the autoformatter incorrectly requires all features and it's loaded first (the list is sorted alphabetically :D) – https://github.com/ckeditor/ckeditor5-autoformat/issues/5.

In this case, either we should check the command later on, on runtime, or, like in https://github.com/ckeditor/ckeditor5-autoformat/issues/5, we need a post init event.

[Reinmar]

Requires https://github.com/ckeditor/ckeditor5-core/issues/42.