DOC Note on _contributors.rst as its presence is now clearer
+
+..
+
+ This file maps contributor names to their URLs. It should mostly be used
+ for core contributors, and occasionally for contributors who do not want
+ their github page to be their URL target. Historically it was used to
+ hyperlink all contributors' names, and ``:user:`` should now be preferred.
+
+
.. _Olivier Grisel: https://twitter.com/ogrisel
.. _Gael Varoquaux: http://gael-varoquaux.info
