[css-color-adjust-1][editorial] fix markup

Author: tabatkins

css-color-adjust-1/Overview.bs

@@ -717,7 +717,7 @@ The 'color-adjust' Shorthand {#color-adjust}
 
 	<pre class="propdef shorthand">
 	Name: color-adjust
-	Value: <'print-color-adjust'>
+	Value: <<'print-color-adjust'>>
 	</pre>
 
 	The 'color-adjust' shorthand allows an author