docs: fix incorrect syntax for MatchPattern (#1148)

Author: jason-hwang

docs/guide/essentials/content-scripts.md

@@ -603,7 +603,7 @@ export default defineContentScript({
   matches: ['*://*.youtube.com/*'],
   main(ctx) {
     ctx.addEventListener(window, 'wxt:locationchange', ({ newUrl }) => {
-      if (watchPattern.matches(newUrl)) mainWatch(ctx);
+      if (watchPattern.includes(newUrl)) mainWatch(ctx);
     });
   },
 });