Update the developer docs to note the ability to log in with your Git…

…Hub account

src/doc/en/developer/trac.rst

@@ -30,9 +30,19 @@ the `Sage trac timeline <http://trac.sagemath.org/timeline>`_.
 Obtaining an Account
 ====================
 
-You need a trac account if you want to *change* anything on the Sage trac
-server, even if you just want to comment on a ticket. To obtain one, send an
-email to ``sage-trac-account@googlegroups.com`` containing:
+**New:** Previously, it was necessary to manually request a Trac account in
+order to post anything to Sage's Trac.  Now, if you have a GitHub account, you
+may log in using it to create and comment on tickets, and edit wiki pages on
+Sage's Trac.
+
+A manual account request is currently only necessary if you prefer not to use
+GitHub, if you wish to use the ``git trac`` git plugin (the ``git trac`` plugin
+is useful for beginners, but is not be necessary for experienced git users), or
+you want to log into the old `Sage Wiki <https://wiki.sagemath.org>`_. This may
+change as well in the future.
+
+To obtain a non-GitHub account, send an email to
+``sage-trac-account@googlegroups.com`` containing:
 
 * your full name,
 * preferred username,