Use code blocks in order to allow easier copy-pasting

Currently when you copy these code snippets, quotes are formatted wrongly, resulting in errors.

Author: JakobGM

docs/source/scripts.rst

@@ -22,14 +22,13 @@ if you work on multiple projects, you want it to be specific to the project
 you are currently working on. Wouldn't it be nice if it was set based on the
 active virtualenv? You can achieve this with :ref:`scripts` as follows.
 
-If your :ref:`WORKON_HOME <variable-WORKON_HOME>` is set to ~/.virtualenvs:
+If your :ref:`WORKON_HOME <variable-WORKON_HOME>` is set to ~/.virtualenvs::
 
     vim ~/.virtualenvs/premkvirtualenv
 
-Edit the file so it contains the following (for a default Django setup):
+Edit the file so it contains the following (for a default Django setup)::
 
     # Automatically set django settings for the virtualenv
-    
     echo "export DJANGO_SETTINGS_MODULE=$1.settings" >> "$1/bin/activate"
 
 Create a new virtualenv, and you should see DJANGO_SETTINGS_MODULE in your env!