Check the docs with a strict build

This treats warnings as errors.

Author: xylar

.github/workflows/build_workflow.yml

@@ -114,7 +114,7 @@ jobs:
           load_script=$(find . -maxdepth 1 -type f -name 'load_compass*.sh' | sort | tail -n 1)
           source "$load_script"
           cd docs
-          make html
+          make html-strict
 
       - if: ${{ steps.skip_check.outputs.should_skip != 'true' }}
         name: Run Tests

docs/Makefile

@@ -12,7 +12,10 @@ BUILDDIR      = _build
 help:
 	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
 
-.PHONY: help Makefile
+.PHONY: help html-strict Makefile
+
+html-strict:
+	@$(SPHINXBUILD) -M html "$(SOURCEDIR)" "$(BUILDDIR)" -W $(SPHINXOPTS) $(O)
 
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).