Adding a tip to mention that the given steps to start ssh-agent may not work for all (#26974)

Co-authored-by: mc <42146119+mchammer01@users.noreply.github.com>

content/authentication/keeping-your-account-and-data-secure/reviewing-your-ssh-keys.md

@@ -63,6 +63,8 @@ You can delete unauthorized (or possibly compromised) SSH keys to ensure that an
 
   {% data reusables.desktop.windows_git_for_windows_turn_on_ssh_agent %}
 
+  {% indented_data_reference reusables.desktop.note-start-ssh-agent spaces=3 %}
+
 1. Find and take a note of your public key fingerprint.
 
    ```shell

content/authentication/troubleshooting-ssh/error-permission-denied-publickey.md

@@ -77,6 +77,9 @@ $ ssh -T git@{% data variables.command_line.codeblock %}
 1. {% data reusables.desktop.windows_git_bash_turn_on_ssh_agent %}
 
   {% data reusables.desktop.windows_git_for_windows_turn_on_ssh_agent %}
+  
+  {% indented_data_reference reusables.desktop.note-start-ssh-agent spaces=3 %}
+  
 1. Verify that you have a private key generated and loaded into SSH.
 
    ```shell

data/reusables/desktop/note-start-ssh-agent.md

@@ -0,0 +1,5 @@
+{% tip %}
+
+**Note:** The eval commands above start ssh-agent manually in your environment. These commands may fail if ssh-agent already runs as a background system service. If that happens, we recommend you check the relevant documentation for your environment.
+
+{% endtip %}

data/reusables/desktop/windows_git_bash_turn_on_ssh_agent.md

@@ -1,7 +1,7 @@
 **If you are using Git Bash**, turn on ssh-agent:
 
-```shell
-# start the ssh-agent in the background
-$ eval "$(ssh-agent -s)"
-> Agent pid 59566
-```
+    ```shell
+    # start the ssh-agent in the background
+    $ eval "$(ssh-agent -s)"
+    > Agent pid 59566
+    ```

data/reusables/desktop/windows_git_for_windows_turn_on_ssh_agent.md

@@ -1,7 +1,7 @@
 **If you are using another terminal prompt**, such as [Git for Windows](https://git-for-windows.github.io/), turn on ssh-agent:
 
-```shell
-# start the ssh-agent in the background
-$ eval $(ssh-agent -s)
-> Agent pid 59566
-```
+    ```shell
+    # start the ssh-agent in the background
+    $ eval $(ssh-agent -s)
+    > Agent pid 59566
+    ```