Update compiler error message for E0761

[Zerotask]

The compiler error message for E0761

should include the src folder and it should use double quotes, similar to the help message of compiler error E0583:

Before

error[E0761]: file for module `user` found at both user.rs and user\mod.rs

After

error[E0761]: file for module `user` found at both "src\user.rs" and "src\user\mod.rs"

[0xPoe]

@rustbot claim