API Guide: Typo in "get citation for dataset" API docs

[pdurbin]

There's an extra {version}:

The file to edit is source/api/native-api.rst.

Here's how it looks as of 6.1: https://guides.dataverse.org/en/6.1/api/native-api.html#get-citation

[DS-INRAE]

It would be a good opportunity to add something on the version parameter like

:latest-published : the latest published version
:latest : either a draft (if exists) or the latest published version.
:draft : the draft version, if any
x.y : x.y a specific version, where x is the major version number and y is the minor version number.

(shamelessly copy-pasted from pyDataverse :) )