docs: fix broken link

demo/nextjs/lib/auth.ts

@@ -15,20 +15,14 @@ export const auth = betterAuth({
 	}),
 	emailAndPassword: {
 		enabled: true,
-		async sendResetPassword(token, user) {
+		async sendResetPassword(url, user) {
 			const res = await resend.emails.send({
 				from,
 				to: user.email,
 				subject: "Reset your password",
 				react: reactResetPasswordEmail({
 					username: user.email,
-					resetLink: `${
-						process.env.NODE_ENV === "development"
-							? "http://localhost:3000"
-							: process.env.NEXT_PUBLIC_APP_URL ||
-								process.env.VERCEL_URL ||
-								process.env.BETTER_AUTH_URL
-					}/reset-password/${token}`,
+					resetLink: url,
 				}),
 			});
 		},