Update deprecate_kwarg message
DOC: add intersphinx mapping to numpy

There are already some references in the API docs to numpy functions, but the links did not yet work up to now.
Merge pull request #7945 from jorisvandenbossche/depr_message

Update deprecate_kwarg message
Merge pull request #7946 from jorisvandenbossche/intersphinx_numpy

DOC: add intersphinx mapping to numpy
ENH: New `level` argument for DataFrame.tz_localize and DataFrame.tz_convert (GH7846)
dummy/stub tz_convert() and tz_localize() method for PeriodIndex
TST: don't test tz_localize and tz_convert on PeriodIndex if not implemented