Docs: Add a `@since` note about new parameters with the spread operator added...

Docs: Add a `@since` note about new parameters with the spread operator added to function signatures.

Props jrf.
See #47678.
Built from https://develop.svn.wordpress.org/trunk@46451


git-svn-id: https://core.svn.wordpress.org/trunk@46249 1a063a9b-81f0-0310-95a4-ce76da25c4cd