Simplify and update verify-templating.yml

This makes it print out a diff when there is an error (instead of just a list of files that are wrong), which will make the error more obvious.

Author: tianon

.github/workflows/verify-templating.yml

@@ -15,9 +15,5 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: Apply Templates
-        run: ./apply-templates.sh
-      - name: Check Git Status
-        run: |
-          status="$(git status --short)"
-          [ -z "$status" ]
+      - run: ./apply-templates.sh
+      - run: git diff --exit-code