Typing overloads for ge, gt, le, lt, eq, ne

[s-banach]

Description

For example, __ge__ is annotated as follows:

    @overload
    def __ge__(self, other: Expr) -> Expr:  # type: ignore[overload-overlap]
        ...

    @overload
    def __ge__(self, other: Any) -> Series:
        ...

Where as ge is annotated like this:

    def ge(self, other: Any) -> Self | Expr:
        """Method equivalent of operator expression `series >= other`."""
        return self.__ge__(other)

Now this is partially a question about how other type checkers work. My experience with Pylance is that I'm going to get a type error from the following code, because x.gt(0).all() could be an Expr:

x = pl.Series(...)
if x.ge(0).all():
    ...

Is this also the case for other type checkers? If so, I can make a quick PR to add these overloads.
(Ironically, I believe Pylance would infer the correct types if ge simply had no annotations at all.)