perf-stream-locked-section: advertise the right version key in the help
As the v3 format is still experimental, its key is "v3-exp". The help text was
not pointing that out.
(we also fix `perf::stream-generate` in the process)
def run(): from . import demandimport with demandimport.tracing.log('hg script'): demandimport.enable() from . import dispatch dispatch.run()if __name__ == '__main__': run()