Improve comments

Author: adbridge

.github/workflows/main.yml

@@ -10,12 +10,12 @@ jobs:
       - name: Checkout repo
         uses: actions/checkout@v2
 
-      - name: Python stuff
+      - name: Install Python environment
         uses: actions/setup-python@v2
         with:
           python-version: 3.8
 
-      - name: Checkout mbed-os-scripts repo
+      - name: Checkout mbed-os-scripts repo (This repo is currently private)
         uses: actions/checkout@v2
         with:
           repository: ARMmbed/mbed-os-ci-scripts