specify cookiecutter branch, use shortcut for github URL

Steve Piercy

2017-06-02 813b7c636a77c0a1a182f9390cfadd0a452c5d2a

 docs/tutorials/modwsgi/index.rst

@@ -39,7 +39,7 @@
    .. code-block:: bash

       $ cd ~
       $ cookiecutter https://github.com/Pylons/pyramid-cookiecutter-starter
       $ cookiecutter gh:Pylons/pyramid-cookiecutter-starter --checkout 1.8-branch

    If prompted for the first item, accept the default ``yes`` by hitting return.