[css-nesting-1][editorial] Clean up some examples slightly.

Author: tabatkins

css-nesting-1/Overview.bs

@@ -805,8 +805,8 @@ Nesting Selector: the ''&'' selector {#nest-selector}
 
 		<pre class=lang-css>
 		.a1, .a2, .a3 {
-			& .b1, & .b3, & .b3 {
-				& .c1, & .c2, & .c3 {
+			.b1, .b3, .b3 {
+				.c1, .c2, .c3 {
 					...;
 				}
 			}
@@ -873,7 +873,8 @@ Nesting Selector: the ''&'' selector {#nest-selector}
 		but only if it's also a <{div}> element".
 
 		It could also be written as ''div&'' with the same meaning,
-		but that wouldn't be valid to start a [=directly nested=] [=style rule=].
+		but that wouldn't be valid to start a [=nested style rule=]
+		(but it could be used somewhere other than the very start of the selector).
 	</div>