Rustify some code.

src/lib.rs

@@ -295,8 +295,6 @@ where
 
 #[cfg(test)]
 mod tests {
-    use std::f64;
-
     use approx::{AbsDiffEq, RelativeEq};
 
     use super::*;
@@ -306,12 +304,10 @@ mod tests {
     impl AbsDiffEq for Rating {
         type Epsilon = f64;
 
-        #[inline]
         fn default_epsilon() -> Self::Epsilon {
             f64::default_epsilon()
         }
 
-        #[inline]
         fn abs_diff_eq(&self, other: &Self, epsilon: Self::Epsilon) -> bool {
             self.mu.abs_diff_eq(&other.mu, epsilon) && self.sigma.abs_diff_eq(&other.sigma, epsilon)
         }
@@ -338,7 +334,11 @@ mod tests {
         let alice = Rating::new(MU, SIGMA);
         let bob = Rating::new(MU, SIGMA);
 
-        assert_relative_eq!(quality(&[&[alice], &[bob]]), 0.4472135954999579, epsilon = EPSILON);
+        assert_relative_eq!(
+            quality(&[&[alice], &[bob]]),
+            0.4472135954999579,
+            epsilon = EPSILON
+        );
     }
 
     #[test]