[css-inline-3] -top/-bottom vs -over/-under

[fantasai]

We historically have had top/bottom values for vertical-align etc; but in vertical text these don't make a whole lot of sense, since they're on the left or right of the line.

For the <text-edge> values introduced by #10713 , what do we want to do?

• Keep text-top and text-bottom, introduce ideographic-top and ideographic-bottom, for consistency.
• Keep text-top and text-bottom, introduce ideographic-over and ideographic-under, keeping consistency with existing keywords, but establishing a new pattern going forward.
• Use text-over and text-under, breaking consistency with vertical-align; and introduce ideographic-over and ideographic-under.

[MurakamiShinyu]

I don't think ideographic-over/under is better than ideographic-top/bottom. I prefer ideographic-top and ideographic-bottom for consistency with existing text-top and text-bottom keywords, and for similarity with OpenType Baseline Tags such as idtp (ideographic top).