[css-scroll-snap] fix example

Author: tabatkins

css-scroll-snap/Overview.bs

@@ -476,7 +476,7 @@ Scroll Snapping Alignment: the 'scroll-snap-align' property {#scroll-snap-align}
 		The following example aligns the center of each city
 		to the center of the scroll container's <a>snap viewport</a>,
 		snapping only when the city is centered in both axes:
-		<pre>city { scroll-snap-align: center point; }</pre>
+		<pre>city { scroll-snap-align: point center; }</pre>
 
 		The following example aligns the center of each photo
 		to the center of the scroll container's <a>snap viewport</a>,
@@ -561,7 +561,7 @@ Scroll Snapping Alignment: the 'scroll-snap-align' property {#scroll-snap-align}
 	and no <a>scroll axis keyword</a> is specified, then
 	the <<snap-alignment>> value
 	applies to the scrollable axis of the affected <a>scroll container</a>.
-	If both axes are scrollable 
+	If both axes are scrollable
 	(i.e. both 'overflow-x' and 'overflow-y' are either ''overflow/scroll'' or ''overflow/auto''),
 	then it applies to the block axis of the affected <a>scroll container</a>
 	(as determined by the <a>scroll container</a>’s <a>writing mode</a>).
@@ -597,7 +597,7 @@ Scroll Snapping Alignment: the 'scroll-snap-align' property {#scroll-snap-align}
 		so are consistent with that syntax.
 		We chose to use this simpler syntax without lengths
 		because the 'scroll-snap-area' concept already provides length offsets--
-		but does so in a smarter way, that degrades better on small screens 
+		but does so in a smarter way, that degrades better on small screens
 		(see above) because it provides more information (a box, rather than a point) to the UA.
 		We could have also added lengths here,
 		but it would provide multiple ways to do the same thing,