DOC, MAINT: Spell check and break long lines in ufunc_docstrings.py.
DOC, MAINT: Spell check and break long lines in ufunc_docstrings.py.

Some bits are also rephrased and nan is replaced by NaN where
appropriate.

NextThought/pypy-numpy,NextThought/pypy-numpy,NextThought/pypy-numpy,NextThought/pypy-numpy