Auto merge of #5491 - smklein:borrowed_box, r=flip1995

Fix issue #2907.

Update the "borrow box" lint to avoid recommending the following
conversion:

```
  // Old
  pub fn f(&mut Box<T>) {...}

  // New
  pub fn f(&mut T) {...}
```

Given a mutable reference to a box, functions may want to change
"which" object the Box is pointing at.

This change avoids recommending removing the "Box" parameter
for mutable references.

changelog: Don't trigger [`borrow_box`] lint on `&mut Box` references

0 files changed, 0 insertions, 0 deletions