fixend themes naming in makefile

docs/Makefile

@@ -41,7 +41,7 @@ help:
 clean:
 	-rm -rf $(BUILDDIR)/*
 
-html: _themes
+html: themes
 	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
 	@echo
 	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."
@@ -66,7 +66,7 @@ json:
 	@echo
 	@echo "Build finished; now you can process the JSON files."
 
-htmlhelp: _themes
+htmlhelp: themes
 	$(SPHINXBUILD) -b htmlhelp $(ALLSPHINXOPTS) $(BUILDDIR)/htmlhelp
 	@echo
 	@echo "Build finished; now you can run HTML Help Workshop with the" \
@@ -152,6 +152,7 @@ doctest:
 	@echo "Testing of doctests in the sources finished, look at the " \
 	      "results in $(BUILDDIR)/doctest/output.txt."
 
-_themes:
+themes:
+	@echo "Updating _themes git submodule"
 	cd ..; git submodule update --init --recursive; cd docs;