AccName term "CSS textual content" for pseudo elements is undefined/ambiguous

[cookiecrook]

AccName "Name from content"
https://w3c.github.io/accname/#comp_name_from_content

…instructs engines to prepend or append "CSS textual content", an undefined term that readers might interpret as not including CSS alternative text. This was formerly an alt: property, but now uses the content: "text" / "alt"; syntax to account for the cascade.

https://drafts.csswg.org/css-content/#alt

I'd suggest ARIA WG liaison with CSS WG to create a term of reference in a CSS spec, and ARIA can link to it.

Note: discovered while working on:

• AccName: Name From Contents Tests web-platform-tests/wpt#42354
• Related AccName algo probably needs an update for ::marker #203

[cookiecrook]

Another FYI @fantasai