Rollup merge of #85672 - CDirkx:ip, r=Mark-Simulacrum
Move stability attribute for items under the `ip` feature
The `#[unstable]` attribute for items under the `ip` feature is currently located on the `std::net::ip` module itself. This is unusual, and less readable. This has sidetracked discussion about these items numerous times (https://github.com/rust-lang/rust/pull/60145#issuecomment-498016572, https://github.com/rust-lang/rust/pull/76098#discussion_r530463543, https://github.com/rust-lang/rust/pull/76098#discussion_r558067755, https://github.com/rust-lang/rust/pull/75019#discussion_r467464300, https://github.com/rust-lang/rust/pull/75019#issuecomment-672888727) and lead to incorrect assumptions about which items are actually stable (https://github.com/rust-lang/rust/pull/60145#issuecomment-485970669, https://github.com/rust-lang/rust/pull/76098#discussion_r530444275).
This PR moves the attribute from the module to the items themselves.
7caf93fa1b