conf: wrap filter() in list()
Python3 shenanigans.
Closes
@@ -134,7 +134,7 @@ html_theme = 'default'
# 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 = filter(os.path.exists, ['_static'])
+html_static_path = list(filter(os.path.exists, ['_static']))
# If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
# using the given strftime format.
