Don't use is_null in are_collinear

nalgebra-glm/src/gtx/vector_query.rs

@@ -9,7 +9,7 @@ use crate::traits::Number;
 ///
 /// * [`are_collinear2d()`]
 pub fn are_collinear<T: Number>(v0: &TVec3<T>, v1: &TVec3<T>, epsilon: T) -> bool {
-    is_null(&v0.cross(v1), epsilon)
+    abs_diff_eq!(v0.cross(v1), T::zero(), epsilon = epsilon)
 }
 
 /// Returns `true` if two 2D vectors are collinear (up to an epsilon).