Add clarification about default run-name in Actions (#31946)

Co-authored-by: Lucas Costi <[email protected]>

Author: thesnowrose

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

@@ -32,7 +32,7 @@ The name of your workflow. {% data variables.product.prodname_dotcom %} displays
 {% ifversion actions-run-name %}
 ## `run-name`
 
-The name for workflow runs generated from the workflow. {% data variables.product.prodname_dotcom %} displays the workflow run name in the list of workflow runs on your repository's "Actions" tab. If you omit `run-name`, the run name is set to event-specific information for the workflow run. For example, for a workflow triggered by a `push` or `pull_request` event, it is set as the commit message.
+The name for workflow runs generated from the workflow. {% data variables.product.prodname_dotcom %} displays the workflow run name in the list of workflow runs on your repository's "Actions" tab. If `run-name` is omitted or is only whitespace, then the run name is set to event-specific information for the workflow run. For example, for a workflow triggered by a `push` or `pull_request` event, it is set as the commit message.
 
 This value can include expressions and can reference the [`github`](/actions/learn-github-actions/contexts#github-context) and [`inputs`](/actions/learn-github-actions/contexts#inputs-context) contexts.