webcommands: unpack contents of length-1 dict portably
((k,v),) = dict.items() was suggested by some friends, but I feel like
that's maybe too clever?
Differential Revision: https://phab.mercurial-scm.org/D2304
@echo off
powershell -NoProfile -ExecutionPolicy unrestricted -Command "& '%~dp0\editmergeps.ps1' %*"