Make the device auth instructions more clear. (#7745)

- [x] Make the device auth instructions more clear.

Author: mzeng-openai

codex-rs/login/src/device_code_auth.rs

@@ -141,7 +141,7 @@ fn print_device_code_prompt(code: &str) {
     println!(
         "\nWelcome to Codex [v{ANSI_GRAY}{version}{ANSI_RESET}]\n{ANSI_GRAY}OpenAI's command-line coding agent{ANSI_RESET}\n\
 \nFollow these steps to sign in with ChatGPT using device code authorization:\n\
-\n1. Open this link in your browser\n   {ANSI_BLUE}https://auth.openai.com/codex/device{ANSI_RESET}\n\
+\n1. Open this link in your browser and sign in to your account\n   {ANSI_BLUE}https://auth.openai.com/codex/device{ANSI_RESET}\n\
 \n2. Enter this one-time code {ANSI_GRAY}(expires in 15 minutes){ANSI_RESET}\n   {ANSI_BLUE}{code}{ANSI_RESET}\n\
 \n{ANSI_GRAY}Device codes are a common phishing target. Never share this code.{ANSI_RESET}\n",
         version = env!("CARGO_PKG_VERSION"),