[css-inline] Disallow `auto` in `text-box` shorthand

[nt1m]

text-box: auto is quite confusing, because it means text-box: trim-both, not text-box: normal.

I suggest we just stop allowing auto within the shorthand. All the combinations with auto already have alternative representations without it.

cc @kojiishi @fantasai

[astearns]

(waiting for more responses before trying an async resolution)

[kojiishi]

I'm neutral, I'd like to defer to better English speakers. Other values such as cap or none look similar to auto to me, but I'm not sure if this is because of my English skill.

[astearns]

The CSSWG will automatically accept this resolution one week from now if no objections are raised here. Anyone can add an emoji to this comment to express support. If you do not support this resolution, please add a new comment.

Proposed Resolution: Drop the auto value in the text-box shorthand

[astearns]

RESOLVED: Drop the auto value in the text-box shorthand