[css-grid] Simplify description of normal sizing. w3c#5713 (comment)

Author: fantasai

css-grid-1/Overview.bs

@@ -1116,22 +1116,22 @@ Grid Items</h2>
 
 	: ''align-self/normal''
 	::
-		If the grid item is a [=replaced element=] with a [=natural size=] in the relevant dimension
-		(or with a [=preferred aspect ratio=] and a size in the other dimension)
-		the grid item is sized as for ''align-self: start''
-		(consistent with the width calculation rules for block-level replaced elements in [[CSS2/visudet#block-replaced-width]]).
+		If the grid item has no [=preferred aspect ratio=],
+		and no [=natural size=] in the relevant axis (if it is a [=replaced element=]),
+		the grid item is sized as for ''align-self: stretch''.
 
 		Otherwise,
-		if the grid item has a [=preferred aspect ratio=],
-		the grid item is sized as for a [=block-level box=].
+		the grid item is sized
+		consistent with the size calculation rules for block-level elements
+		for the corresponding axis.
+		(See [[CSS2#q10.0]].)
 
-		Otherwise,
-		the grid item is sized as for ''align-self/stretch''.
 
 	: ''align-self/stretch''
 	::
 		Use the [=inline size=] calculation rules for non-replaced boxes
-		(defined in [[CSS2/visudet#blockwidth]]).
+		(defined in [[CSS2/visudet#blockwidth]]),
+		i.e. the [=stretch-fit size=].
 
 		Note: This can distort the aspect ratio
 		of an item with a [=preferred aspect ratio=],

css-grid-2/Overview.bs

@@ -1163,22 +1163,21 @@ Grid Items</h2>
 
 	: ''align-self/normal''
 	::
-		If the grid item is a [=replaced element=] with a [=natural size=] in the relevant dimension
-		(or with a [=preferred aspect ratio=] and a [=natural size=] in the other dimension)
-		the grid item is sized as for ''align-self: start''
-		(consistent with the width calculation rules for block-level replaced elements in [[CSS2/visudet#block-replaced-width]]).
+		If the grid item has no [=preferred aspect ratio=],
+		and no [=natural size=] in the relevant axis (if it is a [=replaced element=]),
+		the grid item is sized as for ''align-self: stretch''.
 
 		Otherwise,
-		if the grid item has a [=preferred aspect ratio=],
-		the grid item is sized as for a [=block-level box=].
-
-		Otherwise,
-		the grid item is sized as for ''align-self/stretch''.
+		the grid item is sized
+		consistent with the size calculation rules for block-level elements
+		for the corresponding axis.
+		(See [[CSS2#q10.0]].)
 
 	: ''align-self/stretch''
 	::
 		Use the [=inline size=] calculation rules for non-replaced boxes
-		(defined in [[CSS2/visudet#blockwidth]]).
+		(defined in [[CSS2/visudet#blockwidth]]),
+		i.e. the [=stretch-fit size=].
 
 		Note: This can distort the aspect ratio
 		of an item with a [=preferred aspect ratio=],