Fixed docs/Makefile (#226)

Co-authored-by: Dmitriy Suponitskiy <[email protected]>

Author: dsuponitskiy

docs/Makefile

@@ -13,6 +13,15 @@ help:
 
 .PHONY: help Makefile
 
+# I got the following warning running "make html":
+#     WARNING: html_static_path entry '_static' does not exist
+# The _static folder in a Sphinx project is used to store custom static files. We must either
+# suppress the warning by creating the folder or remove the entry from conf.py ("html_static_path = []").
+# Creating the folder may be safer.
+html:
+	@mkdir -p _static
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(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).
 %: Makefile