Update README.md

Noticed that the README says a `mistral-demo` CLI command should be available, and then goes on to use `mistral-chat` in the example.

I found that `mistral-chat ` and `mistral-demo` are both available, so made the amendment to this line, however I have no idea how to use `mistral-demo`, so no example was added for that.

README.md

@@ -37,7 +37,7 @@ snapshot_download(repo_id="mistralai/mamba-codestral-7B-v0.1", allow_patterns=["
 
 ### Chat
 
-After installing `mistral_inference`, a `mistral-demo` CLI command should be available in your environment.
+After installing `mistral_inference`, `mistral-demo` and `mistral-chat` CLI commands should be available in your environment.
 
 ```
 mistral-chat $HOME/mistral_models/mamba-codestral-7B-v0.1 --instruct  --max_tokens 256