Split contributing docs from user guide

Author: jim-parry

contributing/index.rst

@@ -2,13 +2,13 @@
 Contributing to CodeIgniter
 ###########################
 
-- `Contribution guidelines<./guidelines.rst>`_
-- `Contribution workflow<./workflow.rst>`_
-- `Contribution signing<./signing.rst>`_
-- `Framework internals<./internals.rst>`_
-- `CodeIgniter documentation<./documentation.rst>`_
+- `Contribution guidelines <./guidelines.rst>`_
+- `Contribution workflow <./workflow.rst>`_
+- `Contribution signing <./signing.rst>`_
+- `Framework internals <./internals.rst>`_
+- `CodeIgniter documentation <./documentation.rst>`_
 - `PHP Style Guide <./styleguide.rst>`_
-- `Developer's Certificate of Origin<../DCO.txt>`_
+- `Developer's Certificate of Origin <../DCO.txt>`_
 
 CodeIgniter is a community driven project and accepts contributions of code
 and documentation from the community. These contributions are made in the form