[css-cascade-5][editorial] Fix singular/plural typo #6522

Author: mirisuzanne

css-cascade-5/Overview.bs

@@ -1620,7 +1620,7 @@ Declaring Without Styles: the ''@layer'' statement at-rule</h5>
 	as well as everywhere ''@layer'' [=block at-rules=] are allowed.
 
 	Note: Empty ''@layer'' rules are not allowed between ''@import'' and ''@namespace'' rules.
-	Any ''@layer'' rules that comes after an ''@import'' or ''@namespace'' rule
+	A ''@layer'' rule that comes after an ''@import'' or ''@namespace'' rule
 	will cause any subsequent ''@import'' or ''@namespace'' rules to be ignored.
 
 	Unlike the [[#layer-block|block syntax]],