DOC: fixed typo in linalg.eigh eigvals parameter description

Hi!

There's a typo in the docstring of scipy.linalg.eigh suggesting to use `eigvals=(0,1)` for computing the first eigenvector/-value pair, while it should be `eigvals=(0,0)` instead.
This commit fixes the typo ("lo <= hi" instead of "lo < hi").

Best, Jan