Refactoring documentation of class methods

[Melkiades]

"Methods for listing_df objects" is the documentation page that can be retrieved from print.listing_df. I think there some methods belong to different contexts, e.g. decoration and printing. It has been frustrating at times to get these documentation pages and difficult to understand essential development aspects like the fact that print is essential cat(toString()). This can be largely improved by grouping and extending the documentation, as many of these are directly called by users.

This is more relevant in formatters as the number of internal methods for S4 objects is quite extensive. see: insightsengineering/formatters#142

[shajoezhu]

I think we can close this issue here. This should live inside for formatters