ACTION-2032: Provide a new example for the accessibility api explanatory text.

Replace "For example, Toggle and Invoke patterns can be combined to express a tri-state button."

with

For Example, the TreeItem Control Type is required to support the ExpandCollapse Pattern, because expanding and collapsing is what defines a tree item. Tree items can optionally have other behaviors, and so the TreeItem Control Type can also choose to implement the Invoke control pattern if the tree item can perform a command, ScrollItem control pattern if the tree is scrollable, and the SelectionItem control pattern if it is possible to have an active selection that is maintained when the user returns to the tree container.

Cynthia's text above was incorporated into Jason's branch, see:
https://github.com/w3c/aria/pull/279

Rawgit version:
http://rawgit.com/w3c/aria/ACTION-1569-%282%29/core-aam/core-aam.html#uia

Note for Cynthia:

Put code tags around UIA keywords and remove capital "E" on "Example".

code tags https://github.com/w3c/aria/pull/304

Merged pull request: https://github.com/w3c/aria/pull/304

Is this action finished?

Closed after confirming the text with Cynthia at the AAPI meeting.