Update auth-email.mdx (#20256)

Corrected syntax error.

apps/docs/pages/guides/auth/auth-email.mdx

@@ -38,7 +38,7 @@ async function signUpNewUser() {
     email: 'example@email.com',
     password: 'example-password',
     options: {
-      emailRedirectTo: 'https//example.com/welcome'
+      emailRedirectTo: 'https://example.com/welcome'
     }
   })
 }