Strip the r# prefix from raw identifiers in derive(Debug)

[MaxFreedomPollard]

#[builder(derive(Debug))] treats the r# escape as part of the name, so a builder whose type or members use raw identifiers prints the prefix:

#[derive(Builder)]
#[builder(builder_type = r#type, derive(Debug))]
struct Sut {
    #[builder(start_fn)]
    r#struct: u32,

    #[builder(field)]
    r#enum: u32,

    r#while: u32,
}

let builder = Sut::builder(1).r#while(2);

// On master:
assert_eq!(format!("{builder:?}"), "r#type { r#struct: 1, r#enum: 0, while: 2 }");

The std #[derive(Debug)] prints type, struct and enum for those same names, and bon already does it for the r#while member.

The cause is in bon-macros/src/builder/builder_gen/builder_derives/debug.rs. Named members are formatted with MemberName::snake_raw_str on line 40, which is the name with the prefix removed. The other three names come from Ident::to_string(), which keeps it: the builder struct name passed to Formatter::debug_struct on line 80, #[builder(start_fn)] members on line 14, and #[builder(field)] members on line 27.

All three now use IdentExt::raw_name(), the helper that snake_raw_str is itself built from. #[builder(name = ...)] cannot be combined with start_fn or with field, so for those members the original identifier is the only name they have and stripping the prefix is the whole fix.

The regression test is test_derive_debug in bon/tests/integration/builder/raw_idents.rs. It fails on master with r#type { r#struct: 1, r#enum: 0, while: 2 } and passes here with type { struct: 1, enum: 0, while: 2 }.

Verified on the pinned 1.98.0 toolchain: cargo fmt --check, cargo clippy -p bon -p bon-macros --all-features --all-targets under RUSTFLAGS=--deny warnings, cargo test -p bon-macros --all-features, cargo test -p bon --all-features --doc (7 passed) and cargo test -p bon --all-features --test integration (204 passed). No .stderr snapshot changed.

[Veetaha]

Thanks, I'll make a patch for this