bug#24077: VS: bug in MAN page for data command

[Paul Eggert]

Eric Blake wrote:
> As a compromise, can we mention that MMDDhhmm[[CCYY][.ss]] output can be
> produced by the %m%d%H%M%C%y.%S format, as an additional line of text?

Unfortunately that format does not work when the century is outside the range 
00-99.

Whatever we do, we should do consistently in 'date' and 'touch' and etc.

The POSIX spec uses all lower case, which is confusing in a different way but is 
at least standardized.