Added a note about the total deprecation of YUI

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes
| Applies to    | 2.3+
| Fixed tickets | -

Maybe we could also close the related issue #1841?
I always have the same doubt. In their homepage they use at least four variants: "node.js", "Node", "Node.js" and "Node.js®"