Function cospi is mentioned in the docs but it does not exist on the source

[ElDigoXD]

I was looking for sincospi function and I found in the docs there is "cospi" but not "sinpi", so I looked at the source code and didn't find any reference to them except in docs/build_api.py.

[stijnh]

Good catch! Thanks for your contribution.

If you need it for you code, we could add sinpi/cospi for float and double and for the other precisions fall back to just performing sin(pi*x)/cos(pi*x)

[ElDigoXD]

If its easy/possible to implement, I would like a sincospi function, as I need to compute both.
The cuda one: cuda docs

Thanks!