templater: do not use stringify() to concatenate flattened template output

templater: do not use stringify() to concatenate flattened template output

--- a/mercurial/templater.py	Sat Mar 17 20:04:20 2018 +0900
+++ b/mercurial/templater.py	Sat Mar 17 20:13:06 2018 +0900
@@ -815,7 +815,7 @@
 
     def render(self, t, mapping):
         """Render the specified named template and return result as string"""
-        return templateutil.stringify(self.generate(t, mapping))
+        return b''.join(self.generate(t, mapping))
 
     def generate(self, t, mapping):
         """Return a generator that renders the specified named template and