The original version doesn't render correctly; see, for example,
https://numpy.org/devdocs/reference/generated/numpy.mirr.html#numpy.mirr

The HTML output for the updated markup looks much better.

As per NEP-32, the financial functions are deprecated.

The internal rate of return (irr) is defined as the rate of return
required for the net present values of a series of cashflows to be
zero. i.e the lowest rate of return required for a project to break
even.

This is currently checked by refering to the example output from
the ``irr`` and ``npv`` function documentation. This commit adds a
test to confirm the identity holds.

``np.npv`` calculates the present value of a series of cashflows
starting in the present (t=0). Another common definition of NPV
uses the future cashflows i.e. starting at the end of the first
period.

The difference in definition can lead to confusion for users moving
between NumPy and other projects [1] and adds complexity for
maintainers [2]. This commit adds a warning to the ``npv``
function's documentation and adds an example on how to find the npv
of a project using the alternate definition.

[1] https://github.com/numpy/numpy/issue/10877
[2] https://github.com/numpy/numpy/pull/3346

* ported the refguide_check module from SciPy for usage
in NumPy docstring execution/ verification; added the
refguide_check run to Azure Mac OS CI

* adjusted NumPy docstrings such that refguide_check passes

np.lib.arraypad through np.lib.nanfunctions

Adds support for Decimal to the rate, pv, fv, pmt, ppmt, ipmt, mirr, npv functions

Closes #9781

financial.pmt masked rate array in place, changing rate array.
Changed to mask to a new array, preserving the original rate array.