[css-properties-values-api][editorial] whitespace linting

Author: svgeesus

css-properties-values-api/Overview.bs

@@ -1195,10 +1195,10 @@ The {{CSSPropertyRule}} interface represents an ''@property'' rule.
 <pre class='idl' export>
 [Exposed=Window]
 interface CSSPropertyRule : CSSRule {
-    readonly attribute CSSOMString name;
-    readonly attribute CSSOMString syntax;
-    readonly attribute boolean inherits;
-    readonly attribute CSSOMString? initialValue;
+	readonly attribute CSSOMString name;
+	readonly attribute CSSOMString syntax;
+	readonly attribute boolean inherits;
+	readonly attribute CSSOMString? initialValue;
 };
 </pre>