Support "bpo-" in Misc/NEWS (#1)

Change the url to 2.7

(cherry picked from commit 79ab8be)

Doc/tools/extensions/pyspecific.py

@@ -10,7 +10,7 @@
 """
 
 ISSUE_URI = 'https://bugs.python.org/issue%s'
-SOURCE_URI = 'https://hg.python.org/cpython/file/2.7/%s'
+SOURCE_URI = 'https://github.com/python/cpython/tree/2.7/%s'
 
 from docutils import nodes, utils
 
@@ -58,7 +58,7 @@ def new_depart_literal_block(self, node):
 
 def issue_role(typ, rawtext, text, lineno, inliner, options={}, content=[]):
     issue = utils.unescape(text)
-    text = 'issue ' + issue
+    text = 'bpo- ' + issue
     refnode = nodes.reference(text, text, refuri=ISSUE_URI % issue)
     return [refnode], []