[Numpy-discussion] mean_std function returning both mean and std

I created a solution for ENH: Computing std/var and mean at the same time, issue #23741. The solution can be found here: https://github.com/soundappraisal/numpy/tree/stdmean-dev-001 I still need to add tests and the solution does touch the implementation of var. But before starting a pull request I like to check whether mean_std is a welcome addition. Also I was struggling with the internally needed format of the arrays containing mean and std and the format produced as a result. Which makes me uncertain whether the chosen solution is correct for all cases.