Docs: Show examples of CLI display formats

[rolandcrosby]

A user on the community Slack asked if we have an equivalent to the Postgres/MySQL 'extended' output format. We do -- we call it "records" -- but even after looking at the docs the user didn't realize this. It would be nice to show some simple examples of what each format looks like, perhaps in context here.

[ericharmeling]

I don't really understand what this issue means... Closing for now.

[petervandivier]

Sadly the original conversation seems to have aged out of the Slack community retention policy but IIRC the suggestion was to add examples to the documentation to demonstrate _what_ the various --format options actually do to the output.

At the time it was not clear to me that cockroach --format=records was analogous to psql --expanded. Looking at the docs today it appears that while the valid options set is still listed, there aren't actually examples present to describe (or better yet show) what each does.

[jseldess]

Thanks for clarifying, @petervandivier. I've reopened this.