[css-cascade-5][editorial] Fix nested layer syntax in @import example

Author: mirisuzanne

css-cascade-5/Overview.bs

@@ -158,10 +158,10 @@ Importing Style Sheets: the ''@import'' rule</h2>
 
 	<div class="example">
 		The following layer imports load the style sheets into
-		the ''framework component'' layer, and an un-named layer, respectively:
+		the ''framework.component'' layer, and an un-named layer, respectively:
 
 		<pre>
-		@import url("tabs.css") layer(framework component);
+		@import url("tabs.css") layer(framework.component);
 		@import url("override.css") layer();
 		</pre>
 	</div>