Avoid an inifinite refresh loop when saving the documentation

With make run, listening to any file changes in the destination
directory, the script generating the index files will rerun everytime,
creating a new event, rerunning the generation and so on.
Exclude then any index files under those known subdirectories.

docs/Makefile

@@ -53,7 +53,7 @@ woke-install:
 install: $(VENVDIR) woke-install
 
 run: install
-	. $(VENV); sphinx-autobuild -b dirhtml "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS)
+	. $(VENV); sphinx-autobuild --re-ignore 'reference/policies/.*/index.md' -b dirhtml "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS)
 
 # Doesn't depend on $(BUILDDIR) to rebuild properly at every run.
 html: install