Implement a check when float-only operations are used

[karam-assany]

Feature

Implement a new check that emits an error when the following conditions are met:

1. A name is typed as builtins.float
2. No runtime cast (the_name = float(the_name)) on that name is done
3. A float-only attribute (like builtins.float.hex) on that name is used

This can also be extended for when the builtins.complex.__complex__ attribute (or other complex-only attributes) is used on a builtins.complex-typed name without a runtime cast.

Pitch

This document explains the whole problem.