Document the action=setnotificationtimestamp API on MediaWiki.org
completed by: Allen Guo
mentors: Bartosz Dziewoński
action=setnotificationtimestamp API is not documented anywhere.
The documentation should be created as API:SetNotificationTimestamp page on MediaWiki.org, using a structure similar to other API documentation pages (list here).
Automatically generated documentation can be viewed at https://www.mediawiki.org/w/api.php?action=help&modules=setnotificationtimestamp, your work should expand on it.
In addition, the docs (both on mw.org and in code) should mention something about
marking pages/revisions as visited, since that's how it's called in the UI
("notification timestamp" is an internal term).