Clarifies single line for Python 2 and 3

python3_user_transition_guide.rst

@@ -1,19 +1,14 @@
-Python 3 transition guide
-=========================
-
-Switching to Python 3 can seem like a daunting task, but this guide will
-provide some tips and resources to help make it more straightforward.
-
-Changes you can make today to make the transition easier
---------------------------------------------------------
-
+Writing Python 3 compatible code
+================================
 Any new code you write can easily be Python 3 compatible! This is the first step
-you can take towards switching. Thankfully, the most disruptive changes to the
-language have been back-ported to Python 2 so you can ensure that, when writing
+you can take towards switching. For scientific scripts, being Python 3 combatible
+tends to imply Python 2 compatability.
+
+Thankfully, the most disruptive changes to the
+language have been back-ported to Python 2 so you can ensure that when writing
 new code that you intend to execute with Python 2, it will be executable in
 Python 3 once you switch. To use these back-ported changes, you must import
-certain utilities from the built-in ```__future__``
-<https://docs.python.org/2/library/__future__.html>`_ package. It is generally
+certain utilities from the built-in ``__future__`` package. It is generally
 recommended that, if you are still writing Python 2 compatible code, you should
 import the following four modules in any code you write::