[docs] Doc and comment spelling fixes (issue 27076)

[vadmium+py at gmail.com]

https://bugs.python.org/review/27076/diff/17296/Lib/numbers.py
File Lib/numbers.py (left):

https://bugs.python.org/review/27076/diff/17296/Lib/numbers.py#oldcode38
Lib/numbers.py:38: If it is given heterogenous arguments, and doesn't
have special
I understand the original is also a valid spelling, so we should
probably leave this alone.

https://bugs.python.org/review/27076/diff/17296/Lib/unittest/test/test_case.py
File Lib/unittest/test/test_case.py (left):

https://bugs.python.org/review/27076/diff/17296/Lib/unittest/test/test_case.py#oldcode945
Lib/unittest/test/test_case.py:945: # comparing heterogenous
non-hashable sequences
See other comment about “heterogenous”

https://bugs.python.org/review/27076/