Update doc comment

crates/fj-math/src/vector.rs

@@ -88,6 +88,8 @@ impl<const D: usize> Vector<D> {
     }
 
     /// Compute the angle between this vector and another
+    ///
+    /// Returns a zero angle, if the magnitude of `self` or `other` is zero.
     pub fn angle_to(&self, other: &Self) -> Scalar {
         let product = self.magnitude() * other.magnitude();
         if product.is_zero() {