REST API mailings documentation issues.

[rmuit]

Sorry, no PR.

I just noticed a difference in the return value between https://www.copernica.com/en/documentation/restv2/rest-get-publisher-emailings and https://www.copernica.com/en/documentation/restv2/rest-get-publisher-emailings -- in v3 these are missing in the docs:

* errors: Number of errors for this mailing
* unsubscribes: Number of unsubscribes for this mailing
* abuses: Number of abuses for this mailing

...however they are actually returned. Not sure if they were deleted by accident, or restored in a later version or v3, or ....

The "publisher/destinations" call (i.e. a full list of destinations from/to a certain date) works, but is not documented in the list at https://www.copernica.com/en/documentation/restv3/rest-api.

This unlike the "ms/destinations" call which is documented.

(AFAICT this call is fairly crucial for getting MS statistics and less crucial for Publisher, but it's still nice to know it exists.
Though I could also be wrong on the "less crucial" part; getting to know the differences between the two systems, is a bit of a challenge at first sight :) )