slab allows out-of-bounds access in `get_disjoint_mut` due to incorrect bounds check

slab is a pre-allocated storage for a uniform data type. In version 0.4.10, the get_disjoint_mut method incorrectly checked if indices were within the slab's capacity instead of its length, allowing access to uninitialized memory. This could lead to undefined behavior or potential crashes. This has been fixed in slab 0.4.11. A workaround for this issue involves to avoid using get_disjoint_mut with indices that might be beyond the slab's actual length.