### What it does
Checks for printing on *stderr*. The purpose of this lint
is to catch debugging remnants.

### Why is this bad?
People often print on *stderr* while debugging an
application and might forget to remove those prints afterward.

### Known problems
* Only catches `eprint!` and `eprintln!` calls.
* The lint level is unaffected by crate attributes. The level can still
  be set for functions, modules and other items. To change the level for
  the entire crate, please use command line flags. More information and a
  configuration example can be found in [clippy#6610].

[clippy#6610]: https://github.com/rust-lang/rust-clippy/issues/6610#issuecomment-977120558

### Example
```
eprintln!("Hello world!");
```