diff -r 42d031560294 -r 73b1c328a7da mercurial/util.py
--- a/mercurial/util.py	Tue Sep 20 23:48:19 2016 +0000
+++ b/mercurial/util.py	Tue Sep 20 23:48:30 2016 +0000
@@ -1953,7 +1953,7 @@
         except ValueError:
             raise Abort(_("invalid day spec: %s") % date[1:])
         if days < 0:
-            raise Abort(_('%s must be nonnegative (see "hg help dates")')
+            raise Abort(_("%s must be nonnegative (see 'hg help dates')")
                 % date[1:])
         when = makedate()[0] - days * 3600 * 24
         return lambda x: x >= when