actions: update the documentation with context examples

actions/example-pull-request/.forgejo/workflows/test.yml

@@ -133,10 +133,10 @@ jobs:
 
       - name: save event
         run: |
-          d=/srv/example/pull-request/${{ github.event.pull_request.head.repo.owner.username }}/$GITHUB_EVENT_NAME/${{ github.event.action }}
+          d=/srv/example/pull-request/contexts/${{ github.event.pull_request.head.repo.owner.username }}/$GITHUB_EVENT_NAME
           mkdir -p $d
-          cat > $d/event <<'EOF'
-          ${{ toJSON(github.event) }}
+          cat > $d/github <<'EOF'
+          ${{ toJSON(github) }}
           EOF
 
       - uses: https://code.forgejo.org/actions/checkout@v4