Sphinxify the developer policy document.

llvm-svn: 158814
diff --git a/llvm/docs/userguides.rst b/llvm/docs/userguides.rst
index 0d1f3fb..57058ee 100644
--- a/llvm/docs/userguides.rst
+++ b/llvm/docs/userguides.rst
@@ -7,6 +7,7 @@
    :hidden:
 
    CommandGuide/index
+   DeveloperPolicy
    FAQ
    Lexicon
 
@@ -32,7 +33,7 @@
    A walk through the process of using LLVM for a custom language, and the
    facilities LLVM offers in tutorial form.
 
-* `Developer Policy <DeveloperPolicy.html>`_
+* :ref:`developer_policy`
 
    The LLVM project's policy towards developers and their contributions.