PR-comment automation works now. Fix nits

Author: kainino0x

.github/workflows/pr-comment.yml

@@ -40,9 +40,9 @@ jobs:
           comment-author: 'github-actions[bot]'
           body-includes: "<!-- pr-comment -->"
 
-      # If 'requested'
+      # If 'pr' workflow run was 'requested'...
       - if: github.event.action == 'requested'
-        name: If 'requested' - Update Comment
+        name: PR workflow started - Update Comment
         uses: peter-evans/create-or-update-comment@v5
         with:
           issue-number: ${{ steps.pr-context.outputs.number }}
@@ -52,9 +52,9 @@ jobs:
             <!-- pr-comment -->
             Waiting for [build job](https://github.com/${{github.repository}}/actions/runs/${{github.event.workflow_run.id}}) (at ${{ github.event.workflow_run.head_sha }})...
 
-      # If 'completed'
+      # If 'pr' workflow run was 'completed'...
       - if: github.event.action == 'completed'
-        name: If 'completed' - Download pr-comment-body.txt
+        name: PR workflow completed - Download pr-comment-body.txt
         uses: actions/download-artifact@v4
         continue-on-error: true
         with:
@@ -63,7 +63,7 @@ jobs:
           run-id: ${{ github.event.workflow_run.id }}
           name: pr-comment-body.txt
       - if: github.event.action == 'completed'
-        name: If 'completed' - Create pr-comment.txt
+        name: PR workflow completed - Create pr-comment.txt
         env:
           REPO: ${{github.repository}}
           RUN_ID: ${{github.event.workflow_run.id}}
@@ -85,7 +85,7 @@ jobs:
             fi
           ) > pr-comment.txt
       - if: github.event.action == 'completed'
-        name: If 'completed' - Update Comment
+        name: PR workflow completed - Update Comment
         uses: peter-evans/create-or-update-comment@v5
         with:
           issue-number: ${{ steps.pr-context.outputs.number }}

.github/workflows/pr.yml

@@ -39,10 +39,10 @@ jobs:
           tools/validate --print-case-count-report src/webgpu > case-count-report-after.txt
       - name: checkout before PR
         env:
-          PR_REF: ${{ github.event.pull_request.base.ref }}
+          PR_BASE_REF: ${{ github.event.pull_request.base.ref }}
         run: |
-          git fetch origin "${PR_REF}"
-          git checkout "${PR_REF}"
+          git fetch origin "${PR_BASE_REF}"
+          git checkout "${PR_BASE_REF}"
       - name: compute case count before PR and diff
         id: case_count_diff
         run: |