[Appendix D 1.4] Add shmem_my_pe as a standard way to get process ID

[kwaters4]

For OpenSHMEM the standard function is shmem_team_my_pe(). While this function called with SHMEM_TEAM_WORLD (shmem_team_my_pe(SHMEM_TEAM_WORLD)) is the same as calling shmem_my_pe(), I believe the text should include both shmem_team_my_pe() and shmem_my_pe() as "standard" ways to provide ids for OpenSHMEM PEs. shmem_my_pe is used later in Example 54and across the document.