Fix typo in comment in PYRAMIDS_cm (#163)
Fix typo in comment in PYRAMIDS_cm (#163)

The number of local regions is 3 times the number of pyramid blocks
since the inner and outer air regions are actually the same numbered
region.

marenaud/EGSnrc,nrc-cnrc/EGSnrc,MartinMartinov/EGSnrc,MartinMartinov/EGSnrc,ftessier/EGSnrc,MartinMartinov/EGSnrc,nrc-cnrc/EGSnrc,nrc-cnrc/EGSnrc,nrc-cnrc/EGSnrc,mchamberland/EGSnrc,mchamberland/EGSnrc,ftessier/EGSnrc,ftessier/EGSnrc,crcrewso/EGSnrc,MartinMartinov/EGSnrc,marenaud/EGSnrc,MartinMartinov/EGSnrc,mchamberland/EGSnrc,nrc-cnrc/EGSnrc,mchamberland/EGSnrc,crcrewso/EGSnrc,marenaud/EGSnrc,marenaud/EGSnrc,ftessier/EGSnrc,marenaud/EGSnrc,crcrewso/EGSnrc,crcrewso/EGSnrc,crcrewso/EGSnrc,marenaud/EGSnrc,ftessier/EGSnrc,ftessier/EGSnrc,mchamberland/EGSnrc,mchamberland/EGSnrc