Correct typo in quaternion documentation (#559)

Correct "looses" to "loses" in quaternion.rs documentation.

src/geometry/quaternion.rs

@@ -856,15 +856,15 @@ impl<N: Real> UnitQuaternion<N> {
 
     /// Compute the exponential of a quaternion.
     ///
-    /// Note that this function yields a `Quaternion<N>` because it looses the unit property.
+    /// Note that this function yields a `Quaternion<N>` because it loses the unit property.
     #[inline]
     pub fn exp(&self) -> Quaternion<N> {
         self.as_ref().exp()
     }
 
     /// Compute the natural logarithm of a quaternion.
     ///
-    /// Note that this function yields a `Quaternion<N>` because it looses the unit property.
+    /// Note that this function yields a `Quaternion<N>` because it loses the unit property.
     /// The vector part of the return value corresponds to the axis-angle representation (divided
     /// by 2.0) of this unit quaternion.
     ///