[css-view-transitions-1][editorial] Refactor elemental concepts

* Make rules about grouping/flattening due to view-transition-name into a subsection of the property definition.
* Expand out the text of the 3D flattening rule, so that it is reasonably self-evident without following the link.
* Rename “involved in a view transition” to “captured in a view transition” to better link related concepts by using more closely related terminology.
* Move transition suppression impacts under its definition, since these impacts are why that concept exists.

Author: fantasai

css-view-transitions-1/Overview.bs

@@ -499,8 +499,8 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 	</pre>
 
 	The 'view-transition-name' property “tags” an element
-	as potentially [=involved in a view transition=],
-	capturing it independently in the [=view transition tree=]
+	for [=capture in a view transition=],
+	tracking it independently in the [=view transition tree=]
 	under the specified <dfn>view transition name</dfn>.
 	An element so captured is animated independently of the rest of the page.
 
@@ -534,30 +534,13 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 	this property has no effect.
 	See [[#algorithms]] for exact details.
 
-# Layout and rendering changes # {#layout-rendering-changes}
+### Rendering Consolidation ### {#named-and-transitioning}
 
-## Named and transitioning elements ## {#named-and-transitioning}
-
-	[=/Elements=] have an <dfn export>involved in a view transition</dfn> boolean, initially false.
-
-	[=/Elements=] that either have a 'view-transition-name' [=computed value=] that is not ''view-transition-name/none'',
-	or are [=involved in a view transition=], form:
-
-	- a [=stacking context=].
-
-	- a [[css-transforms-2#grouping-property-values|group]].
-
-	- a [=backdrop root=].
-
-	Note: This spec uses CSS's definition of [=element=], which includes [=pseudo-elements=].
-
-## Interactions during suppressed rendering ## {#interactions-during-suppressed}
-
-	While a {{Document}} |document|'s [=document/transition suppressing rendering=] is true,
-	pointer hit testing must target |document|'s [=document element=],
-	ignoring all other [=elements=].
-
-	Note: This does not effect pointers that are [=pointer capture|captured=].
+	[=/Elements=] [=captured in a view transition=] during a [=view transition=]
+	or whose 'view-transition-name' [=computed value=] is not ''view-transition-name/none'' (at any time):
+	- Form a [=stacking context=].
+	- Are [[css-transforms-2#grouping-property-values|flattened in 3D transforms]].
+	- Form a [=backdrop root=].
 
 # Pseudo-elements # {#pseudo}
 
@@ -892,6 +875,12 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 
 # Concepts # {#concepts}
 
+## Elements ## {#elements-concept}
+
+	[=/Elements=] have a <dfn export>captured in a view transition</dfn> boolean, initially false.
+
+	Note: This spec uses CSS's definition of [=element=], which includes [=pseudo-elements=].
+
 ## Phases ## {#phases-concept}
 
 	<dfn>Phases</dfn> represent an ordered sequence of states.
@@ -958,6 +947,12 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 		: <dfn>transition suppressing rendering</dfn>
 		:: a boolean. Initially false.
 
+			While a {{Document}}’s [=document/transition suppressing rendering=] is true,
+			all pointer hit testing must target its [=document element=],
+			ignoring all other [=elements=].
+
+			Note: This does not affect pointers that are [=pointer capture|captured=].
+
 		: <dfn>dynamic view transition style sheet</dfn>
 		:: a [=/style sheet=].
 			Initially a new [=/style sheet=] in the [=user-agent origin=], ordered after the [=global view transition user agent style sheet=].
@@ -1264,7 +1259,7 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 					1. [=list/For each=] |capturedElement| of |transition|'s [=ViewTransition/named elements=]' [=map/values=]:
 
 						1. If |capturedElement|'s [=captured element/new element=] is not null,
-							then set |capturedElement|'s [=captured element/new element=]'s [=involved in a view transition=] to true.
+							then set |capturedElement|'s [=captured element/new element=]'s [=captured in a view transition=] to true.
 
 					1. [=Setup transition pseudo-elements=] for |transition|.
 
@@ -1718,7 +1713,7 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 
 					- |capturedElement| has more than one [=box fragment=].
 
-					Note: Other rendering constraints are enforced via |capturedElement|'s [=new element=] being [=involved in a view transition=].
+					Note: Other rendering constraints are enforced via |capturedElement|'s [=new element=] being [=captured in a view transition=].
 
 				1. Set |width| to the current width of |capturedElement|'s [=new element=]'s [=border box=].
 
@@ -1772,7 +1767,7 @@ urlPrefix: https://wicg.github.io/navigation-api/; type: interface;
 		1. [=list/For each=] |capturedElement| of |transition|'s [=ViewTransition/named elements=]' [=map/values=]:
 
 			1. If |capturedElement|'s [=captured element/new element=] is not null,
-				then set |capturedElement|'s [=captured element/new element=]'s [=involved in a view transition=] to false.
+				then set |capturedElement|'s [=captured element/new element=]'s [=captured in a view transition=] to false.
 
 			1. [=list/For each=] |style| of |capturedElement|'s [=captured element/style definitions=]: