Assert an absolute difference is equal to an expression.
Pseudocode: |Δ| = x
use assertables::*; let a = 10; let b = 13; let x = 3; assert_abs_diff_eq_x!(a, b, x);
assert_abs_diff_eq_x
assert_abs_diff_eq_x_as_result
debug_assert_abs_diff_eq_x