Remove non-existant dir "_static" from conf.py

  - readthedocs/readthedocs.org#1776 (comment)

Author: jcameron73

docs/conf.py

@@ -64,4 +64,5 @@
 # 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"]
+html_static_path = []