Assert a function output is greater than another.
Pseudocode: a_function(a) > b_function(b)
use assertables::*; let a: i8 = -2; let b: i8 = 1; assert_fn_gt2!(i8::abs, a, i8::abs, b);
assert_fn_gt2
assert_fn_gt2_as_result
debug_assert_fn_gt2