Set static path correctly

See readthedocs/readthedocs.org#1776 for more
information.

Author: logan2211

doc/source/conf.py

@@ -96,7 +96,7 @@
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['static']
+html_static_path = ['_static']
 
 # Custom sidebar templates, must be a dictionary that maps document names
 # to template names.