[mediaqueries] Define `<media-type>` with basic syntax

[cdoublev]

I understand why <media-type> is defined with <ident> instead of the known media types, which are defined in prose. But would you accept defining the known media types with a basic syntax, in order to be extracted by w3c/reffy? Or to define <media-type> as follows, and to define in prose that <ident> should be chosen only if other alternations do not match?

           <media-type> = all | print | screen | <deprecated-media-type> | <ident>
<deprecated-media-type> = tty | tv | projection | handheld | braille | embossed | aural | speech

Actually, I think it can be defined with <media-type> = all | print | screen | <ident> because not unknown, not tty, unknown, tty, must evaluate to false.

User agents must recognize the following media types as valid, but must make them match nothing.

An unknown <media-type> must be treated as not matching.

[cdoublev]

After considering this note:

It is expected that all of the media types will also be deprecated in time

The change is not worth it.