[css-position-3][editorial] Tweaks to containing block adjustments section.

Author: fantasai

css-position-3/Overview.bs

@@ -380,24 +380,24 @@ Containing Blocks of Positioned Boxes</h3>
 </div>
 
 <h4 id="original-cb">
-Further Shrinking the Containing Block</h4>
+Further Adjustments to the Containing Block</h4>
 
-	Some features can additionally change the [=containing block=]
+	Some features can alter the effective [=containing block=] rectangle
 	of [=absolutely positioned=] boxes.
 	These are applied in the following order,
-	with earlier steps modifying the containing block
+	with earlier steps modifying the [=containing block=]
 	that later steps see:
 
-	1. If the [=containing block=] is generated by a [=grid container=],
-		the [=grid-placement properties=]
-		on the positioned element
-		change the [=containing block=]
-		to the corresponding [=grid area=]
-		of that [=grid container=].
+	1. The [=grid-placement properties=]
+		on an [=absolutely positioned box=]
+		whose [=containing block=] is generated by a [=grid container=]
+		can change the [=containing block=] rectangle
+		to a specified [=grid area=].
 		See [[css-grid-1#abspos-items]].
 
-	2. If 'inset-area' has an effect on the positioned element,
-		the [=containing block=] is the specified area of the [=inset-area grid=].
+	2. The 'inset-area' and 'position-try' properties
+		can change the [=containing block=] rectangle
+		to a specified area of an [=inset-area grid=].
 		See [[css-anchor-position-1#inset-area]].
 
 	The element's <dfn export>original containing block</dfn>