Apply Zhian's suggestions

Co-authored-by: Zhian N. Kamvar <zkamvar@gmail.com>

.github/workflows/template.yml

@@ -77,6 +77,7 @@ jobs:
       - name: Sync lesson with carpentries/styles
         working-directory: lesson
         run: |
+          echo "::group::Fetch Styles"
           if [[ -n "${{ github.event.pull_request.number }}" ]]
           then
             ref="refs/pull/${{ github.event.pull_request.number }}/head"
@@ -89,31 +90,38 @@ jobs:
 
           git remote add styles https://github.com/carpentries/styles.git
           git fetch styles $ref:styles-ref
-
+          echo "::endgroup::"
+          echo "::group::Synchronize Styles"
           # Sync up only if necessary
           if [[ $(git rev-list --count HEAD..styles-ref) != 0 ]]
           then
 
             # The merge command below might fail for lessons that use remote theme
             # https://github.com/carpentries/carpentries-theme
+            echo "Testing merge using recursive strategy, accepting upstream changes without committing"
             if ! git merge -s recursive -Xtheirs --no-commit styles-ref
             then
 
               # Remove "deleted by us, unmerged" files from the staging area.
               # these are the files that were removed from the lesson
               # but are still present in the carpentries/styles repo
+              echo "Removing previously deleted files"
               git rm $(git diff --name-only --diff-filter=DU)
 
               # If there are still "unmerged" files,
               # let's raise an error and look into this more closely
               if [[ -n $(git diff --name-only --diff-filter=U) ]]
               then
+                echo "There were unmerged files in ${{ matrix.lesson-name }}:"
+                echo "$(git diff --compact-summary --diff-filter=U)"
                 exit 1
               fi
             fi
 
+            echo "Committing changes"
             git commit -m "Sync lesson with carpentries/styles"
           fi
+          echo "::endgroup::"
 
       - name: Look for R-markdown files
         id: check-rmd