Math: cross-link dot product and cross product docs.

src/Magnum/Math/Vector.h

@@ -111,7 +111,10 @@ the same general direction, `1` when two *normalized* vectors are parallel,
 * *normalized* vectors are antiparallel. @f[
     \boldsymbol a \cdot \boldsymbol b = \sum_{i=0}^{n-1} \boldsymbol a_i \boldsymbol b_i
 @f]
-@see @ref Vector::dot() const, @ref Vector::operator-(), @ref Vector2::perpendicular()
+@see @ref Vector::dot() const, @ref Vector::operator-(),
+    @ref Vector2::perpendicular(),
+    @ref cross(const Vector3<T>&, const Vector3<T>&),
+    @ref cross(const Vector2<T>&, const Vector2<T>&)
 */
 template<std::size_t size, class T> inline T dot(const Vector<size, T>& a, const Vector<size, T>& b) {
     T out{};

src/Magnum/Math/Vector3.h

@@ -54,7 +54,8 @@ gives the direction of its normal, and
 is its area. Length of a cross product is also related to a distance of a point
 and a line, see @ref Distance::linePoint(const Vector3<T>&, const Vector3<T>&, const Vector3<T>&)
 for more information.
-@see @ref cross(const Vector2<T>&, const Vector2<T>&), @ref planeEquation()
+@see @ref cross(const Vector2<T>&, const Vector2<T>&), @ref planeEquation(),
+    @ref dot(const Vector<size, T>&, const Vector<size, T>&)
 */
 template<class T> inline Vector3<T> cross(const Vector3<T>& a, const Vector3<T>& b) {
     return {