autosave.js documentation

[carolinegeven]

This patch documents the autosave.js core JavaScript file.
It is part of an ongoing process on documenting all core JavaScript files.
Props go out to ​https://profiles.wordpress.org/terwdan, ​https://profiles.wordpress.org/thulshof, ​https://profiles.wordpress.org/andizer and ​https://profiles.wordpress.org/carolinegeven

Please make sure to give props to the mentioned profiles.

[carolinegeven]

documented autosave.js

[netweb]

Based on the patch's mention of @since 3.9.0 I've switched the version to that and moving to 4.9 for consideration

[adamsilverstein]

In 41265:

Docs: Improve JavaScript documentation in autosave.js.

Add and improve JSDOC blocks.

Props carolinegeven.
Fixes #41203.

[adamsilverstein]

@carolinegeven I inadvertently left off the props for the users mentioned in the description of the ticket. I'll make sure to get their usernames on the list before we release 4.9 if they aren't already from other work.

[carolinegeven]

@adamsilverstein Thank you, much appreciated! :)