10105: RfC: Use `todo!()` instead of `()` for missing fields r=jonas-schievink a=jo-so
Most commonly a field of a struct can be initialized with its default value than an empty tuple.
Co-authored-by: Jörg Sommer <joerg@jo-so.de>
The generated code with `()` doesn't compile in most of the cases. To signal
the developer there's something to do, fill in `todo!()`.
Because the file *missing_fields.rs* contains the string `todo!()` it needs
an exception for the test *check_todo*.
Moving tests to `rust-analyzer` crate allows removing walkdir dependency
from `xtask`. It does seem more reasonable to keep tidy tests outside of
the "build system" and closer to other integration tests.
