[docs] Doc: remove errors about mixed-type comparisons. (issue 12067)

[vadmium+py at gmail.com]

http://bugs.python.org/review/12067/diff/13054/Doc/reference/expressions.rst
File Doc/reference/expressions.rst (right):

http://bugs.python.org/review/12067/diff/13054/Doc/reference/expressions.rst#newcode1093
Doc/reference/expressions.rst:1093: otherwise, :exc:`TypeError` is
raised:
Fine by me. In the previous patch I was referring to two paragraphs up,
that already says “A default order comparision . . . raises
:exc:`TypeError` ”.

http://bugs.python.org/review/12067/diff/13054/Doc/reference/expressions.rst#newcode1100
Doc/reference/expressions.rst:1100: also between different types (for
example, ``1 == 1.0`` is true).
This sounds like 1 and 1.0 were considered unequal before 3.2. Perhaps
you were trying to say that Decimal and Fraction couldn’t be compared
with other types before 3.2?

http://bugs.python.org/review/12067/diff/13054/Doc/reference/expressions.rst#newcode1174
Doc/reference/expressions.rst:1174: 
Not sure. It might also be useful to people using the operators without
implementing them.

http://bugs.python.org/review/12067/