docs: fix audit warning in Python formula example

Auditing a formula with this structure (plus a `desc` statement)
results in an audit warning:

>   * C: 12: col 3: `include` (line 12) should be put before `desc` (line 2)

1 files changed, 3 insertions, 3 deletions

diff --git a/docs/Python-for-Formula-Authors.md b/docs/Python-for-Formula-Authors.md
index 13b96e563..723601afe 100644
--- a/docs/Python-for-Formula-Authors.md
+++ b/docs/Python-for-Formula-Authors.md
@@ -51,7 +51,7 @@ poet some_package
 deactivate
 ```
 
-Homebrew provides helper methods for instantiating and populating virtualenvs. You can use them by putting `include Language::Python::Virtualenv` on the `Formula` class definition, above `def install`.
+Homebrew provides helper methods for instantiating and populating virtualenvs. You can use them by putting `include Language::Python::Virtualenv` at the top of the `Formula` class definition.
 
 For most applications, all you will need to write is:
 
@@ -85,6 +85,8 @@ Installing a formula with dependencies will look like this:
 
 ```ruby
 class Foo < Formula
+  include Language::Python::Virtualenv
+
   url "..."
 
   resource "six" do
@@ -97,8 +99,6 @@ class Foo < Formula
     sha256 "09bfcd8f3c239c75e77b3ff05d782ab2c1aed0892f250ce2adf948d4308fe9dc"
   end
 
-  include Language::Python::Virtualenv
-
   def install
     virtualenv_install_with_resources
   end