Fixed rST formatting of contributing guideline.

CONTRIBUTING.rst

-[![Jazzband](https://jazzband.co/static/img/jazzband.svg)](https://jazzband.co/)
+.. image:: https://jazzband.co/static/img/jazzband.svg
+   :target: https://jazzband.co/
+   :alt: Jazzband
 
-This is a [Jazzband](https://jazzband.co/) project.
-By contributing you agree to abide by the
-[Contributor Code of Conduct](https://jazzband.co/docs/conduct) and follow the
-[guidelines](https://jazzband.co/docs/guidelines).
+This is a `Jazzband <https://jazzband.co>`_ project. By contributing you agree to abide by the `Contributor Code of Conduct <https://jazzband.co/docs/conduct>`_ and follow the `guidelines <https://jazzband.co/docs/guidelines>`_.
 
 Contribute
 ==========