contrib/editmergeps.bat

formatter: remove now-unnecessary check for file-ness

`templater.templatepath()` now returns non-`None` only for files, so
the caller doesn't have to check.

Differential Revision: https://phab.mercurial-scm.org/D8805

@echo off
powershell -NoProfile -ExecutionPolicy unrestricted -Command "& '%~dp0\editmergeps.ps1' %*"