[css-cascade-4] Fix typo: remove an extra article "the" (#7096)

Author: sharonytlau

css-cascade-4/Overview.bs

@@ -92,7 +92,7 @@ Introduction</h2>
 	When different declarations try to set a value for the same element/property combination,
 	the conflicts must somehow be resolved.
 
-	The opposite problem arises when no declarations try to set a the value for an element/property combination.
+	The opposite problem arises when no declarations try to set a value for an element/property combination.
 	In this case, a value is be found by way of <a>inheritance</a>
 	or by looking at the property's <a>initial value</a>.