[css-anchor-position-1] abspos CB -> CB per standard terms

Author: fantasai

css-anchor-position-1/Overview.bs

@@ -426,7 +426,7 @@ in anchor positioning.
 	* |possible anchor| is laid out strictly before |positioned el|,
 		aka one of the following is true:
 		* Both |positioned el| and |possible anchor| are [=absolutely positioned=],
-			and |positioned el|'s [=absolute positioning containing block=] is
+			and |positioned el|'s [=containing block=] is
 			an ancestor of |possible anchor|'s [=absolute positioning containing block=]
 			in the [=containing block chain=].
 
@@ -436,13 +436,13 @@ in anchor positioning.
 			and an ancestor of all [=containing blocks=]
 			generated by elements not in a [=top layer=].
 		* Both |positioned el| and |possible anchor| are [=absolutely positioned=]
-			and have the same [=absolute positioning containing block=],
+			and have the same [=containing block=],
 			and either |positioned el| is [=in a higher top layer=] than |possible anchor|,
 			or they're both in the same [=top layer=]
 			and |positioned el| is later in [=flat tree=] order than |possible anchor|.
 		* |possible anchor| is not [=absolutely positioned=],
 			and its [=containing block=]
-			is either the same as or a descendant of |positioned el|'s [=absolute positioning containing block=].
+			is either the same as or a descendant of |positioned el|'s [=containing block=].
 
 	* If |possible anchor| is in the [=skipped contents=] of another element,
 		then |positioned el| is in the [=skipped contents=] of that same element.