Dash (`-`) in a crate name breaks `rustdoc-scrape-examples`

[WaffleLapkin]

Problem

When a crate has a dash (-) in its name, the unstable rustdoc-scrape-examples option stops working.

Steps

1. Create a crate with a dash in it's name: cargo new --lib da-sh && cd da-sh
2. Add a function to the crate: echo "pub fn f() {}" >> src/lib.rs
3. Add an example that uses the added function: mkdir examples && echo "fn main() { da_sh::f() }" > examples/e.rs
4. Run rustdoc: cargo +nightly doc -Zunstable-options -Zrustdoc-scrape-examples=examples --open
5. Observe documentation of f (example is missing):
6. Remove dash from the crate name: sed -i 's/da-sh/dash/' Cargo.toml && sed -i 's/da_sh/dash/' examples/e.rs
7. Run rustdoc: cargo +nightly doc -Zunstable-options -Zrustdoc-scrape-examples=examples --open
8. Observe documentation of f (example is present):

Possible Solution(s)

No response

Notes

I'm not sure if this is an issue with rustdoc or cargo, maybe this issue should be moved to rustdoc repo.

Version

cargo 1.58.0-nightly (94ca096af 2021-10-29)

[Eh2406]

cc @willcrichton

[willcrichton]

Thanks for the concise repro @WaffleLapkin! I just created a PR for the fix.