Documentation improvement for Zsh which needs ""

docs/cli.md

@@ -362,6 +362,10 @@ poetry add "requests[security,socks]~=2.22.0"
 poetry add "git+https://github.com/pallets/flask.git@1.1.1[dotenv,dev]"
 ```
 
+{{% warning %}}
+Be aware that some shells (in particular Mac Zsh) may not recognise the package name without quotes - for example `poetry add requests[security,socks]`. In this case try instead with quotes `poetry add "requests[security,socks]"`
+{{% /warning %}}
+
 If you want to add a package to a specific group of dependencies, you can use the `--group (-G)` option:
 
 ```bash