Implement SinglePickable for IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr,
SocketAddrV4, SocketAddrV6, and PathBuf

Update repository URLs to use underscore instead of hyphen

Add `#![deny(missing_docs)]` across multiple crates and fill in
documentation for all public items, including struct fields, enum
variants, trait methods, and proc macros.  Also mark two shell scripts
as executable.

- Move PickerArg-to-PickerArgInfo conversion into an `into_info` method
- Add `short_flag()` and `long_flag()` methods to PickerArgInfo

Remove the `Default` bound from `pick()` and `EntryPicker::pick()`,
allowing non-Default types to be used as arguments.

Add `IntoPicker::pick_or`, `pick_or_default`, and `pick_or_route`
convenience methods for common fallback patterns.

Fix token splitting in `arg!` macro to correctly handle angle brackets.

Move the REMAINS constant definition into arg_picker and re-export it
through mingling's constants module for unified access

BREAKING CHANGE: Remove `mingling_support` feature from arg-picker
crate. The
`EntryPicker` trait and `corebind` module are now part of the mingling
crate
directly, and `build_pattern1` is now a public method.