added link to GitHub CLI

Author: rongxin-liu

cs50.dev.md

@@ -183,7 +183,7 @@ curl -L \
 
 Follow [this instruction](https://cs50.readthedocs.io/github/#personal-access-token) to generate a GitHub personal access token.
 
-Alternatively, to get the list of domains required by GitHub Codespaces, execute the following command using GitHub CLI:
+Alternatively, to get the list of domains required by GitHub Codespaces, execute the following command using [GitHub CLI](https://cli.github.com/):
 
 ```bash
 gh api meta | jq .domains.codespaces