Add var service keys to docstring

Author: xenodium

chatgpt-shell.el

@@ -36,10 +36,12 @@
 ;;
 ;; You must set an API key for most cloud services.  Check out:
 ;;
-;;   `chatgpt-shell-openai-key'.
 ;;   `chatgpt-shell-anthropic-key'.
+;;   `chatgpt-shell-deepseek-key'
 ;;   `chatgpt-shell-google-key'.
 ;;   `chatgpt-shell-kagi-key'.
+;;   `chatgpt-shell-openai-key'.
+;;   `chatgpt-shell-openrouter-key'
 ;;   `chatgpt-shell-perplexity-key'.
 ;;
 ;; Alternatively, local services like Ollama do not require an API key.