py3: fix map() use in templatekw.showpredecessors()

Now it matters since hybrid.tobool() no longer consumes the generator.

mercurial/templatekw.py

@@ -567,7 +567,7 b' def showpredecessors(context, mapping):'
     repo = context.resource(mapping, 'repo')
     ctx = context.resource(mapping, 'ctx')
     predecessors = sorted(obsutil.closestpredecessors(repo, ctx.node()))
-    predecessors = map(hex, predecessors)
+    predecessors = pycompat.maplist(hex, predecessors)
 
     return _hybrid(None, predecessors,
                    lambda x: {'ctx': repo[x]},