removed unnecessary async

Former-commit-id: e643654aacb7e3ddaa5a2f0658867de04dc742b4

lib/single-file/processors/lazy/content/content-lazy-loader.js

@@ -116,7 +116,7 @@ this.singlefile.lib.processors.lazy.content.loader = this.singlefile.lib.process
 		return setAsyncTimeout(() => lazyLoadEnd(idleTimeoutId, observer, options, resolve), options.loadDeferredImagesMaxIdleTime);
 	}
 
-	async function deferForceLazyLoadEnd(timeoutId, idleTimeoutId, maxTimeoutId, observer, options, resolve) {
+	function deferForceLazyLoadEnd(timeoutId, idleTimeoutId, maxTimeoutId, observer, options, resolve) {
 		clearAsyncTimeout(maxTimeoutId);
 		return setAsyncTimeout(() => {
 			clearAsyncTimeout(timeoutId);