[css-align-3] Fix link, shorten wording

Author: fantasai

css-align-3/Overview.bs

@@ -2205,15 +2205,15 @@ Determining the Baselines of a Box</h2>
 		<dt>multi-column containers
 		<dd>
 			The first [=baseline set=] of a <a>multi-column container</a>
-			is the first [=baseline set=] of the [=column=] or [=spanner=]
+			is the first [=baseline set=] of the [=column=] or [=multi-column spanner=]
 			with the highest ([=block-start=]&ndash;most) baseline
 			corresponding to the [=multi-column container=]'s [=alignment baseline=].
 			If there is no such line box or child,
 			then the multi-column container has no first [=baseline set=].
 
 			The last [=baseline set=] is analogous,
-			but uses the last [=baseline set=] from the [=column=] or [=spanner=]
-			with the <em>lowest</em> ([=block-end=]&ndash;most) baseline.
+			but uses the <em>last</em> [=baseline set=]
+			and <em>lowest</em> ([=block-end=]&ndash;most) baseline.
 
 		<dt>tables
 		<dd>