[docs] update header in index.rst

- This should stop the top Google link reading 'TLDR'

docs/index.rst

@@ -1,19 +1,22 @@
 ******
-tl;dr
+pex
 ******
+This project is the home of the .pex file, and the ``pex`` tool which can create them.
+``pex`` also provides a general purpose Python environment-virtualization solution similar to `virtualenv <http://virtualenv.org>`_.
+pex is short for "Python Executable"
 
-To quickly get started building .pex (PEX) files, go straight to :ref:`buildingpex`.
+in brief
+===
+To quickly get started building .pex files, go straight to :ref:`buildingpex`.
 New to python packaging?  Check out `packaging.python.org <https://packaging.python.org>`_.
 
-pex
+intro & history
 ===
-
-pex contains the Python packaging and distribution libraries originally available through the 
+pex contains the Python packaging and distribution libraries originally available through the
 `twitter commons <https://github.com/twitter/commons>`_ but since split out into a separate project.
 The most notable components of pex are the .pex (Python EXecutable) format and the
 associated ``pex`` tool which provide a general purpose Python environment virtualization
-solution similar in spirit to `virtualenv <http://virtualenv.org>`_.  PEX files have been used by Twitter
-to deploy Python applications to production since 2011.
+solution similar in spirit to `virtualenv <http://virtualenv.org>`_.  PEX files have been used by Twitter to deploy Python applications to production since 2011.
 
 To learn more about what the .pex format is and why it could be useful for
 you, see :ref:`whatispex`  For the impatient, there is also a (slightly outdated) lightning