webutil: add missing argument to join() stable

webutil: add missing argument to join()

Differential Revision: https://phab.mercurial-scm.org/D7516

--- a/mercurial/hgweb/webutil.py	Wed Nov 20 19:07:02 2019 +0100
+++ b/mercurial/hgweb/webutil.py	Sat Nov 23 23:02:26 2019 -0500
@@ -865,7 +865,7 @@
         raise error.ParseError(_(b'not displayable without template'))
 
     def show(self, context, mapping):
-        return self.join(context, b'')
+        return self.join(context, mapping, b'')
 
     def tobool(self, context, mapping):
         return bool(self._vars)