Auto merge of #5998 - deg4uss3r:master, r=yaahc

Add map_err_ignore lint

In a large code base a lot of times errors are ignored by using something like:

```rust
foo.map_err(|_| Some::Enum)?;
```

This drops the original error in favor of a enum that will not have the original error's context. This lint helps catch throwing away the original error in favor of an enum without its context.

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*Please keep the line below*
changelog: Added map_err_ignore lint

0 files changed, 0 insertions, 0 deletions