DOC: error in description of "direc" parameter of "fmin_powell"

[dwight200]

I think there is a small mistake in the otherwise useful documentation introduced in #9227. Specifically the default is described as np.ones((N, N)) but should be np.eye((N, N))?

Current documentation:

   direc : ndarray, optional
          Initial fitting step and parameter order set as an (N, N) array, where N
          is the number of fitting parameters in `x0`. Defaults to step size 1.0
          fitting all parameters simultaneously (``np.ones((N, N))``). To

Source code (scipy/optimize/optimize.py:_minimize_powell):

      if direc is None:
         direc = eye(N, dtype=float)

[tupui]

Indeed, thanks you for noticing this. Would you do a PR to fix this? Let me know if you want me to do it for you otherwise @dwight200.