search for the title in the entire doc

lib/single-file/single-file-core.js

@@ -229,7 +229,7 @@ const SingleFileCore = (() => {
 				DomProcessorHelper.isolateElement(selectedElement.parentElement, selectedElement);
 				selectedElement.removeAttribute(SELECTED_CONTENT_ATTRIBUTE_NAME);
 			}
-			const titleElement = this.doc.head.querySelector("title");
+			const titleElement = this.doc.querySelector("title");
 			let title;
 			if (titleElement) {
 				title = titleElement.textContent.trim();