array: fix 0d instantiation again

src/array.hpp

@@ -194,7 +194,7 @@ private:
     static constexpr Eigen::Index eigen_shape()
         {
             /* bad Shape handled in matrix() */
-            size_t n = (axis == 0 || Shape::ndim < 2) ? Shape::head : Shape::Tail::head;
+            size_t n = (axis == 0) ? Shape::head : Shape::Tail::head;
             return (n == Dynamic) ? Eigen::Dynamic : n;
         }