Based on various standards which the date/time conversion character suffixes are
inspired by, we defined 'p' and 'P' for lower and upper case am/pm markers (case
switched in beta2 due to request 4989961).

In bug 4962433 we introduced the set of conversions which are capital letters,
e.g. 'X', 'E', and 'T'. There are now four date/time conversion to access the
same set of markers: tp, tP, Tp, and TP. The user must now understand
conversion percedence to reliably predict whether upper or lower case will be
returned.

It would be less confusing if we simply dropped the redundant 'P' date/time suffix.

-- iag@sfbay 2004-06-10