Add details about each of the default behaviors

[stevepiercy]

We could probably write at least a paragraph about each of these explaining what it does in more detail. But this is fine for a start. And maybe the detailed explanation of standard/core behaviors belongs elsewhere than the overview of how to use behaviors.

Originally posted by @davisagli in #1372 (comment)

[Sneha-Goswami123]

Hi, I’d like to work on this issue.
I’m a new contributor exploring documentation contributions for Plone.
Please let me know if I can take this up.

[stevepiercy]

@Sneha-Goswami123 thanks for asking. Please read and follow First-time contributors, especially Things not to do, Contributing to Plone, and Contributing to Volto.

This issue requires a deep understanding of behaviors in Plone. As you can see by the length of the original issue, it's an advanced topic, one not for beginners. I've added appropriate tags to that affect.