DOC: export bindings does not describe the function

[buhtz]

This is about that part of the docu about export bindings
https://ox-hugo.scripter.co/#export-bindings

The key's are described but not the functions behind them.

Of course I know how to describe-key but I assume it would be more helpful for the users to see them in that introduction docu.

describe-key + C-c C-e H A even does not work. It brokes up after C-c C-e and shows me org-export-dispatch.

[kaushalmodi]

Updated the doc page: https://ox-hugo.scripter.co/doc/usage/#export-bindings