Strict subtraction with a signed integer. Computes `self - rhs`, panicking if overflow occurred.
# Panics
## Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
# Examples
Basic usage:
```
# use ::exint::primitive::*;
# ::exint::uint! {
assert_eq!(3_u24.strict_sub_signed(2_i24), 1_u24);
# }
```
The following panics because of overflow:
```should_panic
# use ::exint::primitive::*;
# ::exint::uint! {
let _ = 1_u24.strict_sub_signed(2_i24);
# }
```
```should_panic
# use ::exint::primitive::*;
# ::exint::uint! {
let _ = u24::MAX.strict_sub_signed(-1_i24);
# }
```