[mediaqueries-5] grammar fix

Author: frivoal

mediaqueries-5/Overview.bs

@@ -3143,7 +3143,7 @@ Detecting the desire for reduced data usage when loading a page: the 'prefers-re
 	and immediately switch to downloading smaller assets.
 	User agents are free to implement logic
 	as they see appropriate for situations like these,
-	and also be aware the situations exist.
+	and also ought to be aware the situations exist.
 
 	<div class="example">
 		For example, a site could honour the preference of a user who