[css-grid-3][editorial] Match the other image's style.

Author: tabatkins

css-grid-3/Overview.bs

@@ -1131,12 +1131,10 @@ Alignment and Spacing</h2>
 		<figcaption>
 			The three highlighted items are the only ones with "gaps" following them,
 			so they're the only ones that will respond to 'align-items'.
-			Their [=alignment containers=] are indicated with the hatched areas.
+			Their [=alignment containers=] are indicated by the dashed areas.
 		</figcaption>
 	</figure>
 
-
-
 	ISSUE(10275): Is this a reasonable definition for how the [=self-alignment properties=] should work in the [=stacking axis=]?