What about changing this:
```
  // small -> small (temparray -> smallarray)
  // big   -> small (array -> smallarray)
  // small -> big   (array -> mallocarray)
  // big   -> big   (array -> mallocarray)

  // Check if we're moving from ht_smallarray to ht_smallarray, this can happen
  // when there are many removed items. Copy the items to be able to clean up
  // removed items.
```

into this.

```
  // Check if we're moving from ht_smallarray to ht_smallarray. This can happen
  // when there are many removed items. In that case, copy the items to a temp
  // array (if not, src and dest of the cleanup step would be the same).
```