BUG/DOC: restrict possibilities for assembly of dates using a DataFrame
xref #12967

cc @jorisvandenbossche 
 @shoyer 
 Apart from the doc comment, I would personally even leave out the abbreviations for `minutes` and `seconds`. Then also the possible confusion of `m` as month or minute is avoided (I also never seen 'm' used as abbreviation of minute)
 +1 for leaving out any abbreviations. I'm not even sure it's actually a
good thing to accept both plural and singular forms.

On Tue, Apr 26, 2016 at 4:07 PM, Joris Van den Bossche <
notifications@github.com> wrote:

> Apart from the doc comment, I would personally even leave out the
> abbreviations for minutes and seconds. Then also the possible confusion
> of m as month or minute is avoided (I also never seen 'm' used as
> abbreviation of minute)
> 
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> https://github.com/pydata/pandas/pull/12996#issuecomment-214914504
