Clarify comments

.github/workflows/publish.yml

@@ -29,13 +29,15 @@ jobs:
     steps:
       # Checkout repository
       - uses: actions/checkout@v4
-      # Setup Dart SDK with JWT token
+      # Set up the Dart SDK and provision the OIDC token used for publishing.
+      # The `dart` command from this step will be shadowed by the one from the
+      # Flutter SDK below. 
       - uses: dart-lang/setup-dart@0a8a0fc875eb934c15d08629302413c671d3f672
       # Download flutter SDK - needed for publishing Flutter packages. Can also
       # publish pure Dart packages.
       #
-      # This will add the flutter/bin/dart executable to path, that sets up
-      # FLUTTER_ROOT.
+      # The dart binary from a Flutter SDK facilitates publishing both Flutter
+      # and pure-dart packages.
       - uses: flutter-actions/setup-flutter@d030cb603380106494f72d65a7e52462f380781f
       # Minimal package setup and dry run checks.
       - name: Install dependencies