[css-align] introduction to baseline values should link to "baseline-sharing group" rather than "alignment context"

[dbaron]

The first substantive sentence of the section on baseline alignment values:

Baseline alignment is a form of positional alignment that aligns multiple alignment subjects within a shared alignment context (such as cells within a row or column) by matching up their alignment baselines.

currently links to "shared alignment context". But I think it would make sense to turn that into "baseline-sharing group". This both:

• reduces the number of terms used in the paragraph
• links to a more specific term for what connects the boxes

[dbaron]

I also think the other two links in that section to "alignment context" (in the definitions of first baseline and last baseline) should also be to "baseline-sharing group". Otherwise those definitions incorrectly imply that an alignment context has a baseline.

I also think that the "corresponding baseline of" immediately before those two links is misleading. It seems to imply that that baseline is already established, whereas in reality it is the set of things in the group that together establish the common baseline.

[tabatkins]

The use of "shared alignment context" in the intro is intentional - it's the major constraint on what boxes you can form a baseline-sharing group with, and is the more fundamental concept for what baseline alignment is. (The concept of baseline-sharing group had to be created due to the limitations of trying to align boxes with different writing modes and/or baseline alignment preferences.)

We'll make the second change you request, though (linking to baseline-sharing group rather than alignment context in the definition of the keywords).

We disagree with your third point -- the baseline-sharing group does generate a baseline, to which all the individual boxes align. They are then collectively positioned within their own contexts, establishing the position of that baseline. (When the alignment baselines of individual items are different, this becomes particularly clear, as the baseline-sharing group generates a baseline set not just a single baseline.)

Let us know if you find this resolution satisfactory.