mercurial/__main__.py

rust-index: remove one collect when converting back

Turns out this is slightly faster. Sending the results back to Python is still
the most costly (like 75% of the time) of the whole method, but it's about
as fast as it can be now.

hg perf::phases on mozilla-try-2023-03-22
before: 0.267114
after:  0.247101

def run():
    from . import demandimport

    with demandimport.tracing.log('hg script'):
        demandimport.enable()
        from . import dispatch

        dispatch.run()


if __name__ == '__main__':
    run()