Change bug tracker links to github

Tor is preparing to move to Gitlab. Rather than follow it I'm moving to GitHub.
Just finished migraing our tickets so now updating the bug tracker links.

docs/_templates/layout.html

@@ -51,7 +51,7 @@
             <ul>
               <li><a href="{{ pathto('faq') }}">FAQ</a></li>
               <li><a href="{{ pathto('change_log') }}">Change Log</a></li>
-              <li><a href="https://trac.torproject.org/projects/tor/wiki/doc/stem/bugs">Bug Tracker</a></li>
+              <li><a href="https://github.com/torproject/stem/issues/">Bug Tracker</a></li>
               <li><a href="https://jenkins.torproject.org/job/stem-tor-ci/">Jenkins</a></li>
               <li><a href="{{ pathto('download') }}">Download</a></li>
             </ul>

docs/faq.rst

@@ -532,7 +532,7 @@ How do I get started?
 ---------------------
 
 The best way of getting involved with any project is to jump right in! Our `bug
-tracker <https://trac.torproject.org/projects/tor/wiki/doc/stem/bugs>`_ lists
+tracker <https://github.com/torproject/stem/issues/>`_ lists
 several development tasks. In particular look for the 'easy' keyword when
 getting started. If you have any questions then I'm always more than happy to
 help! I'm **atagar** on `oftc <http://www.oftc.net/>`_ and also available
@@ -543,7 +543,7 @@ know if you get stuck or would like to discuss anything!
 
 #. Clone our `git <http://git-scm.com/>`_ repository: **git clone https://git.torproject.org/stem.git**
 #. Get our test dependencies: **sudo pip install mock pycodestyle pyflakes**.
-#. Find a `bug or feature <https://trac.torproject.org/projects/tor/wiki/doc/stem/bugs>`_ that sounds interesting.
+#. Find a `bug or feature <https://github.com/torproject/stem/issues/>`_ that sounds interesting.
 #. When you have something that you would like to contribute back do the following...
 
  * If you don't already have a publicly accessible Stem repository then set one up. `GitHub <https://github.com/>`_ in particular is great for this.

docs/index.rst

@@ -54,7 +54,7 @@ Stem is a Python controller library for `Tor <https://www.torproject.org/>`_. Wi
    File: Crystal/64x64/apps/bug.png
 
 .. image:: /_static/buttons/bug_tracker.png
-   :target: https://trac.torproject.org/projects/tor/wiki/doc/stem/bugs
+   :target: https://github.com/torproject/stem/issues/
 
 .. Source: ColorCons (http://mouserunner.com/Spheres_ColoCons1_Free_Icons.html)
    Author: Ken Saunders (http://mouserunner.com/MRDS_Cell.html)