Returns `self` with only the least significant bit set, or `0` if the input is `0`.
# Examples
Basic usage:
```
# use ::exint::primitive::*;
# ::exint::uint! {
use exint::Saturating;
assert_eq!(Saturating(0b01100100_i24).isolate_lowest_one(), Saturating(0b00000100_i24));
assert_eq!(Saturating(0_i24).isolate_lowest_one(), Saturating(0_i24));
# }
```