Update Sphinx build command to suppress warnings

Added suppress_warnings option to Sphinx build command.

Author: sba72

.github/workflows/test-build.yml

@@ -33,7 +33,7 @@ jobs:
       - run: git pull
         working-directory: ./Doc/locales/XX/LC_MESSAGES
       - uses: sphinx-doc/github-problem-matcher@v1.1
-      - run: make -e SPHINXOPTS="--color -D language='XX' -W --keep-going" ${{ matrix.format }}
+      - run: make -e SPHINXOPTS="--color -D language='XX' -D suppress_warnings=i18n.inconsistent_references -W --keep-going" ${{ matrix.format }}
         working-directory: ./Doc
       - uses: actions/upload-artifact@master
         if: success() || failure()
@@ -57,4 +57,4 @@ jobs:
       - uses: actions/upload-artifact@master
         with:
           name: build-${{ matrix.version }}-pdf
-          path: .
+          path: .