Add Firefox support information for the Cookie Store API

[chrisdavidmills]

Description

A subset of the Cookie Store API is enabled in Firefox Nightly only, as of Firefox 132. This includes:

• The CookieStore interface, but not partitioned in return values.
• The CookieChangeEvent interface, excluding partitioned properties.
• Window.cookieStore
• ServiceWorkerGlobalScope.cookieStore

It doesn't include:

• The CookieStoreManager interface
• The ExtendableCookieChangeEvent interface
• ServiceWorkerRegistration.cookies
• ServiceWorkerGlobalScope: cookiechange event`

I worked this out by looking at what WebIDL has been exposed in the implementation. See https://phabricator.services.mozilla.com/D215144.

This PR adds notes to the Firefox 132 rel notes and the Experimental features page to explain what support has bene shipped. I'm not sure if we need to think about adding information on how to handle cross-browser Cookie Store API code, or whether it is just case of some stuff doesn't work on Fx.

For the implementation bugs, see:

• https://bugzilla.mozilla.org/show_bug.cgi?id=1475599
• https://bugzilla.mozilla.org/show_bug.cgi?id=1918643

Motivation

Additional details

Related issues and pull requests

Documentation issue: #36122

[github-actions]

Preview URLs

• /en-US/docs/Mozilla/Firefox/Experimental_features
• /en-US/docs/Mozilla/Firefox/Releases/132

External URLs (2)

URL: /en-US/docs/Mozilla/Firefox/Experimental_features
Title: Experimental features in Firefox

• https://bugzil.la/1800882 (2 times) (Note! This may be a new URL 👀)

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URL: /en-US/docs/Mozilla/Firefox/Releases/132
Title: Firefox 132 for developers

• https://bugzil.la/1800882 (1 time) (Note! This may be a new URL 👀)