docs(CDK Overlay): highlight `usePopover` API in the Overview and/or Examples

[michael-small]

Documentation Feedback

Problem

The popover API behavior as of 21 has caused some confusion, and in my opinion could stand to be explained a bit more outside of just the API tab.

Overlay doc API page: https://material.angular.dev/cdk/overlay/api

Two threads that I have noticed a need for this distinction for:

• Angular v21 material overlay + dialog
• How to not open cdk dialog in top-layer.

I'll let those speak for themselves, but to summarize, the popover behavior in v21 has caused some issues for existing applications which have other non-CDK type overlay APIs. And were I to make a fresh app, I would also find this helpful information to know.

Also, even with knowing about that API option, IMO the provider/useValue syntax doesn't immediately jump out to people like me even seeing all the individual pieces on the API page.

Suggestion

Highlight this behavior and how to set it with usePopover in either the "Overview" and/or "Examples" tab ok the CDK Popover doc.

edit: and possibly a note of this in adjacent APIs like dialogs

Effort

I am willing to make a PR if there is agreement/interest

Affected documentation page

https://material.angular.dev/cdk/overlay/api