Fix warnings with static not being found and an indentation error in upgrading.

source/D/upgrading.rst

@@ -19,7 +19,7 @@ Since 18.10 is not an LTS (Long Term Support) release, you may have to opt in fo
     - Close the update manager, and you should be prompted to upgrade to the latest release.
     - .. image:: 03_development_release.png
     - Alternatively, you can start a terminal (Ctrl + Alt + T) and type in the command "update-manager -d"
-        -  The -d flag is referring to the fact that it's moving to an unsupported release (if you are on the LTS track, this is accurate).
+    -  The -d flag is referring to the fact that it's moving to an unsupported release (if you are on the LTS track, this is accurate).
 
 Next, you will want to upgrade to the new release.
     - After rebooting, start the update manager.

source/conf.py

@@ -137,7 +137,7 @@ html_favicon = "manual.ico"
 # 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']
 
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied