API: Allow for documenting individual values of 'prop' parameters

There are cases where the list of values for a 'prop' parameter may be
manipulated by a subclass or by a hook function of some sort. Rather
than requiring the subclass/hook to completely replace a monolithic i18n
message, let's add the possibility of separate messages for each value
in the list.

Bug: T77930
Change-Id: I0bb061c62ebeef125062460e26306c88390f7b31
Merge "API: Allow for documenting individual values of 'prop' parameters"