Callout enhancements

Callout is a great feature. Which I was waiting for, but it does not live up to my expectations.

Before its introduction, I used html blocks. Callout is a great move, but it’s pretty limited.

For example this is how I can do it using 2 html blocks

With the help of your implementation, I cannot do this, but I would like not to write crutches.

It would also be nice to add headers for the Callout and the ability to collapse the main block so that only the header remains.