Docs: unclear that esqiusse_server(data_rv) needs to have a name

[daattali]

Documentation says

A reactiveValues with at least a slot data containing a data.frame to use in the module. And a slot name corresponding to the name of the data.frame.

That wording is ambiguous, mostly because the "and" is in a new sentence, it made me think that only data is required and the name is optional. It also made sense to me, because I would have thought that if a name is not provided then you can just default to a sensible name such as "data" or "df" (maybe you can consider this?)

Additionally, "at least" implies that there are more optional slots - are there more supported slots? If yes, they should be described. If not, then the word "at least" should be removed.