[3.11] Remove Sphinx problem matcher to avoid annotating unchanged files (GH-108005) (#108050)

Co-authored-by: Hugo van Kemenade <[email protected]>

Author: miss-islington

.github/problem-matchers/sphinx.json

@@ -18,8 +18,6 @@ jobs:
     timeout-minutes: 60
     steps:
     - uses: actions/checkout@v3
-    - name: Register Sphinx problem matcher
-      run: echo "::add-matcher::.github/problem-matchers/sphinx.json"
     - name: 'Set up Python'
       uses: actions/setup-python@v4
       with:
@@ -65,8 +63,6 @@ jobs:
     timeout-minutes: 60
     steps:
     - uses: actions/checkout@v3
-    - name: Register Sphinx problem matcher
-      run: echo "::add-matcher::.github/problem-matchers/sphinx.json"
     - uses: actions/cache@v3
       with:
         path: ~/.cache/pip