[css-align][editorial] Add an algo wrapper so the variable can be highlighted.

Author: tabatkins

css-align-3/Overview.bs

@@ -901,25 +901,28 @@ Self-Alignment for Absolutely Positioned Boxes</h5>
 	whose relevant [=self-alignment property=] is not ''justify-self/normal'',
 	the default [=overflow alignment=] behavior is as follows:
 
-	1. Let the |default overflow rect| be the bounding rectangle
-		of the [=alignment subject's=] [=inset-modified containing block=]
-		and its [=original containing block=].
-	2. If the [=alignment subject=] overflows its [=inset-modified containing block=]
-		(its normal [=alignment container=]),
-		but does not overflow |default overflow rect|
-		align as specified (''unsafe'').
-	3. If the <em>size</em> of the [=alignment subject=]
-		fits within the |default overflow rect|,
-		but its specified alignment would cause it to overflow the |default overflow rect|,
-		it is instead shifted the minimum amount
-		to stay within the |default overflow rect|
-		while honoring the alignment as much as possible
-		(i.e., flush with the edge of the [=original containing block=]
-		it was trying to overflow over).
-	4. If the size of the [=alignment subject=]
-		overflows the |default overflow rect|,
-		it is instead start-aligned within the |default overflow rect|
-		(similar to ''safe'').
+
+	<div algorithm="default overflow self-alignment for abspos">
+		1. Let the |default overflow rect| be the bounding rectangle
+			of the [=alignment subject's=] [=inset-modified containing block=]
+			and its [=original containing block=].
+		2. If the [=alignment subject=] overflows its [=inset-modified containing block=]
+			(its normal [=alignment container=]),
+			but does not overflow |default overflow rect|
+			align as specified (''unsafe'').
+		3. If the <em>size</em> of the [=alignment subject=]
+			fits within the |default overflow rect|,
+			but its specified alignment would cause it to overflow the |default overflow rect|,
+			it is instead shifted the minimum amount
+			to stay within the |default overflow rect|
+			while honoring the alignment as much as possible
+			(i.e., flush with the edge of the [=original containing block=]
+			it was trying to overflow over).
+		4. If the size of the [=alignment subject=]
+			overflows the |default overflow rect|,
+			it is instead start-aligned within the |default overflow rect|
+			(similar to ''safe'').
+	</div>
 
 	(For [=absolutely-positioned=] [=alignment subjects=] that fail the above condition,
 	see [[#auto-safety-default]].)