Comment cleanups to improve generated docs

- added comments to fields which didn't have any.
- changed all `//` comments to the new format
- fixed indents/line lengths/style on lines I touched
This field typically means the maximum number of results per page, so if you wanted all of the results, you'd most likely have to use the page tokens to get multiple pages. 

(At least in our backend we take this route in order to prevent a single request from going crazy and pulling wayy too much data. Each request typically has a cap on maxResults - reads is like 1024 and variants is 100 I think? Oh and so null does in fact == 10 in our api)

That said, if a backend wanted to support getting all results at once, perhaps we could document -1 or something?

Either way, this comment is definitely unclear. I'll try to improve a little.