### Summary
Eliminates `IPooledEnumerable<BaseMulti>` and `eable.Free()` from `Map` for multis. This drastically simplifies code that iterates in range, for example:
```cs
foreach (var m in m.GetMultisInRange(5))
{
}
```
The code above no longer requires an eable and calling `Free()`.
### Bug Fixes
- [X] Fixes an issue with searching through nested empty containers.
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