[css-grid-1] Fix Typo (Distortation)

Before: 
>...UAs should attempt to minimize *distortation* of the grid container with respect to unfragmented flow.

After 
>>...UAs should attempt to minimize *distortion* of the grid container with respect to unfragmented flow.

Author: billfienberg

css-grid-1/Overview.bs

@@ -4160,7 +4160,7 @@ Fragmenting Grid Layout</h2>
 
 		<li>
 			Aside from the rearrangement of items imposed by the previous point,
-			UAs should attempt to minimize distortation of the grid container
+			UAs should attempt to minimize distortion of the grid container
 			with respect to unfragmented flow.
 	</ul>