Docs: Document WP_Http_Cookie properties as nullable

[rejaulalomkhan]

Description

In WP_Http_Cookie, the $name and $value properties are initialized to null before the constructor sets them. When $data is passed as an associative array without a name key, the constructor returns early, leaving them uninitialized/null. Documenting both as string|null accurately reflects their lifecycle and satisfies PHPStan.

This resolves the sole error in the booleanOr.alwaysFalse baseline, retiring it, and removes two entries from the isset.property baseline.

Use of AI Tools

Yes, an AI assistant was used for research and static analysis inspection. All changes and baseline updates were manually reviewed, verified, and run locally.

Follow-up to [63899], [64222].
Trac ticket: https://core.trac.wordpress.org/ticket/65817

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[huzaifaalmesbah]

Thanks for working on this, @rejaulalomkhan!

It looks like this overlaps with #13983, which was opened a few days earlier for the same booleanOr.alwaysFalse baseline. That one also documents $domain as nullable and adds unit tests for the constructor's early return.

To avoid splitting review effort, would you be open to closing this in favour of #13983? A review there would be very welcome.

AI Review: Opus 5.5

[rejaulalomkhan]

Thanks @huzaifaalmesbah. #13983 covers the same baseline, also documents $domain as nullable, and adds tests for the constructor’s early return, so it’s the more complete fix. Closing in favour of #13983