[css-highlight-api] Highlight priority attribute should be long instead of double.

Author: sanketj

css-highlight-api-1/Overview.bs

@@ -169,7 +169,7 @@ Creating Custom Highlights</h3>
 	interface Highlight {
 		constructor(CSSOMString name, AbstractRange... initialRanges);
 		setlike<AbstractRange>;
-		attribute double priority;
+		attribute long priority;
 		readonly attribute CSSOMString name;
 	};
 	</xmp>