Simplify ref in markdown

Author: LukeMathWalker

src/numeric/impl_numeric.rs

@@ -46,7 +46,7 @@ impl<A, S, D> ArrayBase<S, D>
         sum
     }
 
-    /// Returns the [`arithmetic mean`] x̅ of all elements in the array:
+    /// Returns the [arithmetic mean] x̅ of all elements in the array:
     ///
     /// ```text
     ///     1   n
@@ -58,7 +58,7 @@ impl<A, S, D> ArrayBase<S, D>
     ///
     /// **Panics** if `A::from_usize()` fails to convert the number of elements in the array.
     ///
-    /// [`arithmetic mean`]: https://en.wikipedia.org/wiki/Arithmetic_mean
+    /// [arithmetic mean]: https://en.wikipedia.org/wiki/Arithmetic_mean
     pub fn mean(&self) -> Option<A>
         where
             A: Clone + FromPrimitive + Add<Output=A> + Div<Output=A> + Zero