update explanation since a lot of it is not needed any more

Author: LorrensP-2158466

tests/pass/float.rs

@@ -23,32 +23,12 @@ use std::{f32, f64};
 /// First: The ULP of a float 'a' is the smallest possible change at 'a', so the ULP difference represents how
 /// many discrete floating-point steps are needed to reach 'b' from 'a'.
 ///
-/// There are 2 techniques we can use to compute the ULP difference of 2 floating-point numbers:
+/// ULP(a) is the distance between the 2 closest floating-point numbers `x` and `y` around `a`, satisfying x < a < y, x != y.
+/// To use this to calculate the ULP difference we have to halve it (we need it at `a`, but we just went "up" and "down", halving it gives us this ULP).
+/// Then take the difference of `b` and `a` and divide it by that ULP and finally round it.
+/// We know now how many floating-point changes we have to apply to `a` to get to `b`.
 ///
-/// ULP(a) is the difference between 'a' and the next larger representable floating-point number.
-/// So to get the ULP difference of `a` and `b`, we can take the absolute difference of
-/// the *unsigned integer* representation of `a` and `b`.
-/// For example checking 2 f32's, which in IEEE format looks like this:
-///
-/// s: sign bit
-/// e: exponent bits
-/// m: significand bits
-/// f32: s | eeee eeee | mmm mmmm mmmm mmmm mmmm mmmm
-/// u32: seee eeee emmm mmmm mmmm mmmm mmmm mmmm
-///
-///
-/// So when the sign and exponent are the same, we can compute a reasonable ULP difference.
-///
-/// But if you know some details of floating-point numbers, it is possible to get 2 values that sit on the border of the exponent,
-/// so `a` can have exponent but `b`  can have a different exponent while still being approximately equal to `a`. For this we can use
-/// John Harrison's definition. Which states that ULP(a) is the distance between the 2 closest floating-point numbers
-/// `x` and `y` around `a`, satisfying x < a < y, x != y. This makes the ULP of `a` twice as large as in the previous defintion and so
-/// if we want to use this, we have to halve it.
-/// This ULP value of `a` can then be used to find the ULP difference of `a` and `b`:
-/// Take the difference of `b` and `a` and divide it by that ULP and finally round it. This is the same value as the first definition,
-/// but this way can go around that exponent border problem.
-///
-/// If this ULP difference is less than or equal to our chosen upper bound
+/// So if this ULP difference is less than or equal to our chosen upper bound
 /// we can say that `a` and `b` are approximately equal, because they lie "close" enough to each other to be considered equal.
 ///
 /// Note: We can see that checking `a` and `b` with different signs has no meaning, but we should not forget
@@ -58,6 +38,7 @@ use std::{f32, f64};
 /// the same amount of "spacing" between all consecutive representable values. So even though 2 very large floating point numbers
 /// have a large value difference, their ULP can still be 1, so they are still "approximatly equal",
 /// but the EPSILON check would have failed.
+///
 fn approx_eq_check<F: Float>(
     actual: F,
     expected: F,