Trying to iterate &Res<Assets<T>> results in a poor compiler error

```rust
for mesh in &meshes {}
```

```rust
error[E0275]: overflow evaluating the requirement `&_: IntoIterator`
|
= help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`scene_viewer`)
= note: required for `&bevy::prelude::Res<'_, _>` to implement `IntoIterator`
= note: 126 redundant requirements hidden
= note: required for `&Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, Res<'_, ...>>>>>>>>>>>>>>>>>>>>>>>>` to implement `IntoIterator`
= note: the full name for the type has been written to '.long-type-3364561052137337366.txt'
= note: consider using `--verbose` to print the full type name to the console

For more information about this error, try `rustc --explain E0275`.
```

Increasing the recursion limit to 256 then says it overflows and suggest increasing to 512, ongoing forever.

The correct solution seems to be using meshes.iter(). I'm curious why that is.