Documentation: convert WritingAnLLVMPass.html to reST.

Patch by Anthony Mykhailenko with small fixes by me.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169992 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/userguides.rst b/docs/userguides.rst
index cfb6dbe..56eaf08 100644
--- a/docs/userguides.rst
+++ b/docs/userguides.rst
@@ -23,6 +23,7 @@
    TestingGuide
    tutorial/index
    ReleaseNotes
+   Passes
 
 * :ref:`getting_started`
     
@@ -58,10 +59,10 @@
    A reference manual for the LLVM command line utilities ("man" pages for LLVM
    tools).
     
-* `LLVM's Analysis and Transform Passes <Passes.html>`_
+* :doc:`Passes`
 
    A list of optimizations and analyses implemented in LLVM.
-    
+
 * :ref:`faq`
 
    A list of common questions and problems and their solutions.