Fix missing section for linux (#29535)

Co-authored-by: Rachael Rose Renk <91027132+rachaelrenk@users.noreply.github.com>

content/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent.md

@@ -223,6 +223,15 @@ If you are using macOS or Linux, you may need to update your SSH client or insta
    ```
 
    {% endwindows %}
+
+   {% linux %}
+
+   ```shell
+   ssh-keygen -t {% ifversion ghae %}ecdsa{% else %}ed25519{% endif %}-sk -C "your_email@example.com"
+   ```
+
+   {% endlinux %}
+
    {%- ifversion not ghae %}
    {% note %}
 
@@ -234,6 +243,7 @@ If you are using macOS or Linux, you may need to update your SSH client or insta
 
    {% endnote %}
    {%- endif %}
+
 1. When you are prompted, touch the button on your hardware security key.
 1. When you are prompted to "Enter a file in which to save the key," press Enter to accept the default file location.