docs for directive ng-container

[Koslun]

I'm submitting a ... (check one with "x")

[ ] bug report => search github for a similar issue or PR before submitting
[ x ] feature request
[ ] support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question

Current behavior

No docs for ng-container. It is however used in the API documentation for:

• NgPluralCase
• NgPlural
• NgSwitch - where it is mentioned "use a ng-container to group multiple root nodes", as referenced in this stackoverflow answer.

Expected behavior

There should be a separate entry in the angular docs where it is listed as a directive along with whether it is stable or experimental. Would have guessed in the section @angular/common but could not find it there after a quick search of the source code so not sure where exactly.

Minimal reproduction of the problem with instructions

Search or look through the docs site.

What is the motivation / use case for changing the behavior?

Given that it is presumably a public directive it would be good to know its usage as well as its stability.

Please tell us about your environment:

• Angular version: 2.0.1

• Browser: [all ]

• Language: [all ]

• Node (for AoT issues): node --version =

[Foxandxss]

Let's continue at #2303 where we have an ongoing discussion.