py3: use range instead of xrange

py3: use range instead of xrange

xrange is not available on Python 3.

Differential Revision: https://phab.mercurial-scm.org/D2074

--- a/tests/test-annotate.py	Wed Feb 07 13:19:19 2018 +0530
+++ b/tests/test-annotate.py	Wed Feb 07 13:21:06 2018 +0530
@@ -27,7 +27,7 @@
 
         def decorate(text, rev):
             return ([annotateline(fctx=rev, lineno=i)
-                     for i in xrange(1, text.count(b'\n') + 1)],
+                     for i in range(1, text.count(b'\n') + 1)],
                     text)
 
         # Basic usage