added support for alpha & colorspace in FF nightly

[dletorey]

Description

• Added release note for alpha & colorspace attributes of <input type="color">:
  • Firefox 149 (experimental section)
  • Firefox Experimental Features

Motivation

• Working on MDN issue #43200

Related issues and pull requests

• BCD PR

[github-actions]

Preview URLs (2 pages)

• /en-US/docs/Mozilla/Firefox/Experimental_features
• /en-US/docs/Mozilla/Firefox/Releases/149

External URLs (2)

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

• https://bugzil.la/1919718 (1 time) (Note! This may be a new URL 👀)

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URL: /en-US/docs/Mozilla/Firefox/Releases/149
Title: Firefox 149 release notes for developers (Beta)

• https://bugzil.la/1919718 (1 time) (Note! This may be a new URL 👀)