float binary ops accept only int/float — no __float__ coercion (Decimal(5) + 2.2 computed 7.2 instead of raising TypeError)

[fgallaire]

>>> Decimal(5) + 2.2
Decimal('7.2')                                                               # before
>>> Decimal(5) + 2.2
TypeError: unsupported operand type(s) for +: 'decimal.Decimal' and 'float'  # after