[Doc] Steps to add a new attention backend (#8155)

.github/workflows/pr-test.yml

@@ -56,7 +56,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        part: [0, 1, 2, 3, 4, 5, 6, 7, 8]
+        part: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
@@ -69,7 +69,7 @@ jobs:
         timeout-minutes: 30
         run: |
           cd test/srt
-          python3 run_suite.py --suite per-commit --auto-partition-id ${{ matrix.part }} --auto-partition-size 9
+          python3 run_suite.py --suite per-commit --auto-partition-id ${{ matrix.part }} --auto-partition-size 10
 
   unit-test-backend-2-gpu:
     if: (github.repository == 'sgl-project/sglang' || github.event_name == 'pull_request') &&