[docs] Add documentation for containerElement in RaisedButon

[Shahrukh-Zindani]

Documentation for containerElement in RaisedButton.
Close issue #5647

[mbrookes]

That doesn't sound quite right...

[Shahrukh-Zindani]

Made a change to that comment. I am still not sure about wording the documentation for containerElement.

[oliviertassinari]

At the very least, we should be consistent with the FlatButton and RaisedButton.
I think that we need the same PR for the next branch, we have a property for the same use case.

[oliviertassinari]

I think that we should make the description generic, i.e. always the same in proptypes documentatino generator.
We have that one on the GridTitle that's a bit too verbose but more explicit:

     /**
     * Either a string used as tag name for the tile root element, or a ReactElement.
     * This is useful when you have, for example, a custom implementation of
     * a navigation link (that knows about your routes) and you want to use it as the primary tile action.
     * In case you pass a ReactElement, please ensure that it passes all props,
     * accepts styles overrides and render it's children.
     */

[Shahrukh-Zindani]

Updated it and made a PR for FlatButton.

[mbrookes]

Could we make the wording consistent across this, #6204, #6210, and any other components that support it?

[Shahrukh-Zindani]

sure.

ok

[Shahrukh-Zindani]

It is consistent between FlatButton, RaisedButton and ListItem. Thanks @lourd for the PR on ListItem.

[Shahrukh-Zindani]

@oliviertassinari Are you sure that containerElement is a prop in the Button tag in the next branch. I tried using it and it does not work nor do I see the prop being defined in the code anywhere.

[oliviertassinari]

@Shahrukh-Zindani Do you want the answer or I let you dig in? (hint: the property name is different and more intuitive)

[Shahrukh-Zindani]

Got it. Let me dig in.