Fix type issue

Author: ajayyy

src/content.ts

@@ -123,7 +123,7 @@ const manualSkipPercentCount = 0.5;
 //get messages from the background script and the popup
 chrome.runtime.onMessage.addListener(messageListener);
 
-function messageListener(request: Message, sender: unknown, sendResponse: (response: MessageResponse) => void): Promise<void> {
+function messageListener(request: Message, sender: unknown, sendResponse: (response: MessageResponse) => void): void {
     //messages from popup script
     switch(request.message){
         case "update":