Update docs to clarify workflow branch for release package publishing. (

#56183)

docs/contributors/code/release.md

@@ -422,7 +422,7 @@ Now, the `wp/X.Y` branch is ready for publishing npm packages. In order to start
 
 ![Run workflow dropdown for npm publishing](https://developer.wordpress.org/files/2023/07/image-2.png)
 
-To publish packages to npm for the WordPress major release, select `wp` from the "Release type" dropdown and enter `X.Y` (example `5.2`) in the "WordPress major release" input field. Finally, press the green "Run workflow" button. It triggers the npm publishing job, and this needs to be approved by a Gutenberg Core team member. Locate the ["Publish npm packages" action](https://github.com/WordPress/gutenberg/actions/workflows/publish-npm-packages.yml) for the current publishing, and have it [approved](https://docs.github.com/en/actions/managing-workflow-runs/reviewing-deployments#approving-or-rejecting-a-job).
+To publish packages to npm for the WordPress major release, select `trunk` as the branch to run the workflow from (this means that the script used to run the workflow comes from the trunk branch, though the packages themselves will published from the release branch as long as the correct "Release type" is selected below), then select `wp` from the "Release type" dropdown and enter `X.Y` (example `5.2`) in the "WordPress major release" input field. Finally, press the green "Run workflow" button. It triggers the npm publishing job, and this needs to be approved by a Gutenberg Core team member. Locate the ["Publish npm packages" action](https://github.com/WordPress/gutenberg/actions/workflows/publish-npm-packages.yml) for the current publishing, and have it [approved](https://docs.github.com/en/actions/managing-workflow-runs/reviewing-deployments#approving-or-rejecting-a-job).
 
 For the record, the manual process would look like the following: