updated "hpcrun -h" documentation to clarify the right way to monitor multiple events in a single execution
updated "hpcrun -h" documentation to clarify the right way to monitor
multiple events in a single execution

zcth428/hpctoolkit,zcth428/hpctoolkit111,HPCToolkit/hpctoolkit,zcth428/hpctoolkit111,HPCToolkit/hpctoolkit,zcth428/hpctoolkit,HPCToolkit/hpctoolkit,zcth428/hpctoolkit111,HPCToolkit/hpctoolkit,zcth428/hpctoolkit,zcth428/hpctoolkit111,HPCToolkit/hpctoolkit,zcth428/hpctoolkit,zcth428/hpctoolkit,HPCToolkit/hpctoolkit,zcth428/hpctoolkit111