Revert "chore: update mastodon account"

This reverts commit 5d88c1855aabe7d0cab8e8d5b9cebcea872bbbb3.

content/.vuepress/head.ts

@@ -123,10 +123,6 @@ simplifiedHead.forEach((tag) => {
     head.push([tag.tag, element]);
   });
 });
-head.push([
-  'a',
-  { rel: 'me', href: 'https://mastodon.phundrak.com/@phundrak' },
-  'Mastodon',
-]);
+head.push(['a', { rel: 'me', href: 'https://emacs.ch/@phundrak' }, 'Mastodon']);
 
 export default head;