The Pull Request #1121 added the `AddressFamily` type to `socket.pyi`
for Python 3.4+, so constants such as `AF_INET` are correctly
represented as being an enum member rather than an int. The same is
true of the `SocketKind` enums in the `SOCK_*` family.
Various functions in the socket module can accept either an int
or an `AF_*` enum member as arguments, which is allowed by the
int argument type. However the `getaddrinfo` function returns an
`AddressFamily` member rather than an int in the first position
of its list members, so code that access enum specific members
such as the `name` attribute causes a typing error to be found.
This change corrects the return type of `getaddrinfo` but leaves
the family parameters as int, given that `AddressFamily` members
are `IntEnum` and only ever treated as `int`s internally.
* Add new methods to socket stubs.
Also fix a couple of invalid types in recv*_into() socket methods.
* Add double-underscores to parameters for position-only arguments
