[css-grid-1] Adjust heading to match previous. w3c#5351 (comment)

Author: fantasai

css-grid-1/Overview.bs

@@ -4328,7 +4328,7 @@ Distributing Extra Space Across Spanned Tracks</h4>
 					then each |item-incurred increase| will be zero.
 
 				<li>
-					<strong>Distribute space beyond growth limits:</strong>
+					<strong>Distribute space beyond limits:</strong>
 					If space remains after all tracks are frozen,
 					unfreeze and continue to distribute space to the |item-incurred increase| of…