Added documentation about escaping values for $GITHUB_ENV file (#21582)

Co-authored-by: Jess Hosman <1183847+jhosman@users.noreply.github.com>

content/actions/using-workflows/workflow-commands-for-github-actions.md

@@ -581,6 +581,8 @@ console.log("The running PID from the main action is: " +  process.env.STATE_pro
 
 During the execution of a workflow, the runner generates temporary files that can be used to perform certain actions. The path to these files are exposed via environment variables. You will need to use UTF-8 encoding when writing to these files to ensure proper processing of the commands. Multiple commands can be written to the same file, separated by newlines.
 
+Most commands in the following examples use double quotes for echoing strings, which will attempt to interpolate characters like `$` for shell variable names. To always use literal values in quoted strings, you can use single quotes instead.
+
 {% powershell %}
 
 {% note %}