Add hint about multiple buttons to Docs/Examples/Customizing/Row buttons

[GitRon]

Dear maintainers!

I need to have more than one button in the action column of my grid. I saw the docs here but it took me a while to figure out that you can just return a list of h elements.

I suggest to add this to the docs, I think having more than one button is a quite common use-case.

Best regards
Ronny