prepend() allows ZeptoCollection arg

zepto/zepto.d.ts

@@ -963,6 +963,12 @@ interface ZeptoCollection {
 	**/
 	prepend(content: HTMLElement[]): ZeptoCollection;
 
+	/**
+	* @see ZeptoCollection.prepend
+	* @param content
+	**/
+	prepend(content: ZeptoCollection): ZeptoCollection;
+
 	/**
 	* Prepend elements of the current collection inside each of the target elements. This is like prepend, only with reversed operands.
 	* @param content