Promote better "API Changes in CKEditor 4"

[Wiktor Walc]

I just spent a couple of minutes on trying to find this article for one user and I did it just because I remembered that something like this existed.

How about:

1. Promoting it somewhere on the front page of docs.ckeditor.com

2. Putting at the top of CHANGES.md something like this:

The list of relevant changes can be found in the ​API Changes page of the CKEditor 4 documentation.

?

[Frederico Caldeira Knabben]

It doesn't make much sense having it at the top of CHANGES.md. This is related to v3 -> CKEditor 4.0 and in fact it is clearly available there already.

A good place for it would be the docs site, in fact.