Update css-nesting-1/Overview.bs

Co-authored-by: Lea Verou <lea@verou.me>

Author: argyleink

css-nesting-1/Overview.bs

@@ -468,7 +468,7 @@ Nesting Conditional Rules {#conditionals}
 	A style rule can have any number of <a>conditional rules</a> inside of it, of any type,
 	with rules required to come after declarations (see <a href="#mixing">Mixing Nesting Rules and Declarations</a>).
 
-	If there are only rules in the nested conditional, the nesting context is adopted.
+	If there are only declarations in the nested conditional, the nesting context is adopted.
 
 	In the presence of a <a>nesting selector</a>, the same
 	rules as outlined in <a href="#direct">direct nesting</a> should be used.
@@ -786,4 +786,4 @@ return the result of the following steps:
 				</ol>
 			<li>Append a newline followed by RIGHT CURLY BRACKET (U+007D) to |s|.
 			<li>Return |s|.
-</ol>
+</ol>