* BUG: properly handle tuple keys in NpZFile.__getitem__

* TST: test tuple rendering specifically.

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Co-authored-by: Ross Barnowski <rossbar@berkeley.edu>

This PR adds additional tests for quantiles:

1. Identification equation $E[V(q, Y)] = 0$
2. Adding a constant $c > 0$: $q(c + Y) = c + q(Y)$
3. Multiplying by a constant $c > 0$: $q(c \cdot Y) = c \cdot q(y)$
4. Multiplying by $-1$: $q_{\alpha}(-Y) = -q_{1-\alpha}(Y)$

(Note by seberg as reviewer: These tests are fairly complex, but may be useful for future development.  But if they seem too complicated, they are probably not really vital and could be shortened or removed.)

Improves the repr to include information about the arrays contained, e.g.:

   >>> npzfile = np.load('arr.npz')
   >>> npzfile
   NpzFile 'arr.npz' with keys arr_0, arr_1, arr_2, arr_3, arr_4...

closes #23319

Co-authored-by: Ross Barnowski <rossbar@berkeley.edu>

ENH: Enabled the use of numpy.vectorize as a decorator

As discussed in
https://mail.python.org/archives/list/numpy-discussion@python.org/thread/UKZJACAP5FUG7KP2AQDPE4P5ADNWLOHZ/

This flag was always meant to be temporary, and cleaning it up is
long overdue.