Fixed all H2 headings

Before, H2 fomratting was not consistent.
Now, all H2 headings use over/under asterisks.

docs/starting/install3/linux.rst

@@ -1,7 +1,9 @@
 .. _install3-linux:
 
+
+############################
 Installing Python 3 on Linux
-============================
+############################
 
 .. image:: /_static/photos/34435689480_2e6f358510_k_d.jpg
 
@@ -42,8 +44,9 @@ to read about `multiple Python versions available in Fedora`_.
 .. _multiple Python versions available in Fedora: https://developer.fedoraproject.org/tech/languages/python/multiple-pythons.html
 
 
+*********************
 Working with Python 3
----------------------
+*********************
 
 At this point, you may have system Python 2.7 available as well.
 
@@ -59,8 +62,10 @@ This will launch the Python 2 interpreter.
 
 This will launch the Python 3 interpreter.
 
+
+****************
 Setuptools & Pip
-----------------
+****************
 
 The two most crucial third-party Python packages are `setuptools <https://pypi.python.org/pypi/setuptools>`_ and `pip <https://pip.pypa.io/en/stable/>`_.
 
@@ -90,8 +95,9 @@ However, when using virtual environments (described below), you don't need to
 care about that.
 
 
+*****************************
 Pipenv & Virtual Environments
------------------------------
+*****************************
 
 The next step is to install Pipenv, so you can install dependencies and manage virtual environments.
 

docs/starting/install3/osx.rst

@@ -2,8 +2,10 @@
 
 .. _install3-osx:
 
+
+###############################
 Installing Python 3 on Mac OS X
-===============================
+###############################
 
 .. image:: /_static/photos/34435689480_2e6f358510_k_d.jpg
 
@@ -17,8 +19,10 @@ good for development. The version shipped with OS X may be out of date from the
 `official current Python release <https://www.python.org/downloads/mac-osx/>`_,
 which is considered the stable production version.
 
+
+**************
 Doing it Right
---------------
+**************
 
 Let's install a real version of Python.
 
@@ -72,14 +76,16 @@ Now, we can install Python 3:
 
 This will take a minute or two.
 
-
+***
 Pip
----
+***
 
 Homebrew installs ``pip`` pointing to the Homebrew'd Python 3 for you.
 
+
+*********************
 Working with Python 3
----------------------
+*********************
 
 At this point, you have the system Python 2.7 available, potentially the
 :ref:`Homebrew version of Python 2 <install-osx>` installed, and the Homebrew
@@ -115,8 +121,9 @@ The rest of the guide will assume that ``python`` references Python 3.
     Python 3.7.1 # Success!
 
 
+*****************************
 Pipenv & Virtual Environments
------------------------------
+*****************************
 
 The next step is to install Pipenv, so you can install dependencies and manage virtual environments.
 

docs/starting/install3/win.rst

@@ -1,7 +1,9 @@
 .. _install3-windows:
 
+
+##############################
 Installing Python 3 on Windows
-==============================
+##############################
 
 .. image:: /_static/photos/34435689480_2e6f358510_k_d.jpg
 
@@ -17,8 +19,10 @@ Once done, installing Python 3 is very simple, because Chocolatey pushes Python
 Once you've run this command, you should be able to launch Python directly from to the console.
 (Chocolatey is fantastic and automatically adds Python to your path.)
 
+
+****************
 Setuptools + Pip
-----------------
+****************
 
 The two most crucial third-party Python packages are `setuptools <https://pypi.python.org/pypi/setuptools>`_ and `pip <https://pip.pypa.io/en/stable/>`_,
 which let you download, install and uninstall any compliant Python software
@@ -30,8 +34,9 @@ All supported versions of Python 3 include pip, so just make sure it's up to dat
     python -m pip install -U pip
 
 
+*****************************
 Pipenv & Virtual Environments
------------------------------
+*****************************
 
 The next step is to install Pipenv, so you can install dependencies and manage virtual environments.