[css-align] Disable baseline alignment in a table column, per WG resolution. Closes #1422

Author: fantasai

css-align/Overview.bs

@@ -356,7 +356,7 @@ Baseline Alignment: the ''baseline'' keyword and ''first''/''last'' modifiers</h
 	<dfn export>Baseline alignment</dfn> is a form of positional alignment
 	that aligns multiple <a>alignment subjects</a>
 	within a <a>shared alignment context</a>
-	(such as cells within a row or column)
+	(such as cells within a row))
 	by matching up their <a>alignment baselines</a>.
 	If the position of the <a>alignment subjects</a> within a <a>baseline-sharing group</a>
 	is not fully constrained by <a>baseline alignment</a>
@@ -683,7 +683,7 @@ The 'justify-content' And 'align-content' Properties</h3>
 	the <a>alignment subject</a> and <a>alignment container</a>
 	both assume the <a>writing mode</a> of the box the '*-content' property is set on.
 
-### Block Containers ### {#distribution-block}
+### Block Containers (Including Table Cells)### {#distribution-block}
 
 	<table class="data align-details">
 		<tr>
@@ -884,8 +884,14 @@ Baseline Content-Alignment</h3>
 		<dt>Table Cells:
 		<dd>
 			A <a>table cell</a> participates in first (last) <a>baseline content-alignment</a>
-			in its startmost (endmost) row or column (whichever is parallel to its <a>inline axis</a>)
-			if its computed 'align-content' is ''first baseline'' (''last baseline'').
+			in its startmost (endmost) row
+			if its inline axis is parallel to that of the table itself and
+			its computed 'align-content' is ''first baseline'' (''last baseline'').
+
+			Note: <a>Baseline content-alignment</a>
+			of cells sharing a column is not supported;
+			however this may be added in a future level
+			if there is sufficient demand and implementer interest.
 
 		<dt>Flex Items:
 		<dd>
@@ -1712,7 +1718,7 @@ Baseline Alignment Grouping</h3>
 
 	<ul>
 		<li>table cells in the same row, along the table's row (inline) axis, established by the row box
-		<li>table cells in the same column, along the table's column (block) axis, established by the column box
+		<!--baseline-align-column <li>table cells in the same column, along the table's column (block) axis, established by the column box -->
 		<li>grid items in the same row, along the grid's row (inline) axis, established by the <a>grid container</a>
 		<li>grid items in the same column, along the grid's column (block) axis, established by the <a>grid container</a>
 		<li>flex items in the same flex line, along the flex container's main axis, established by the <a>flex container</a>
@@ -1787,6 +1793,10 @@ Changes</h2>
 	<ul>
 		<li>Dropped the ''left'' and ''right'' keywords from 'align-self' and 'align-content'.
 			They may be re-introduced in a later level if there is demand.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/1403">Issue 1403</a>)
+		<li>Disabled baseline alignment across cells in a table column,
+			due to implementation complexity.
+
 		<li>A large number of minor corrections and clarifications reported by David Baron.
 	</ul>