JSDoc correction for admin namespaces

[herregroen]

See #41682 for context.

This fixes the same issues for all javascript files in the wp-admin directory.

[herregroen]

Diff can be viewed on Github here:

​https://github.com/Yoast/wordpress-develop-mirror/pull/84

[atimmer]

jsdoc-admin-namespaces.2.patch is a refreshed patch. Created by merging master into the branch using git on the pull request: ​https://github.com/Yoast/wordpress-develop-mirror/pull/84/files.

[atimmer]

In 42403:

Docs: Improve wp-admin JSDoc structural data globally.

JSDoc takes it structural data from @namespace, @lends and @memberOf. This change fixes these tags for all JavaScript files in the wp-admin folder.

• Add jsdoc configuration to parse wp-admin/js files. Use jsdoc -c jsdoc.conf.json to generate JSDoc.
• Define all used namespaces using @namespace.
• Define each usage of the extend function as a prototype assignment using @lends.
• Add @alias if JSDoc cannot detect the correct name automatically.

This has previously been corrected for all wp-includes JavaScript files: [41351].

Props herregroen.
Fixes #42485.