src/tools/clippy/src/docs/main_recursion.txt

### What it does
Checks for recursion using the entrypoint.

### Why is this bad?
Apart from special setups (which we could detect following attributes like #![no_std]),
recursing into main() seems like an unintuitive anti-pattern we should be able to detect.

### Example
```
fn main() {
    main();
}
```