DOC: Fixed formatting and errors in whatsnew v1.1.0
cc @TomAugspurger 

Minor fixes for formatting, spelling, and grammar. Please let me know if any of this is too nit-picky, I can revert to just the definite spelling/syntax errors.
Failure is unrelated. Reported upstream in https://github.com/numpy/numpy/issues/16939.

Thanks @rhshadrach.