Removes elements from a list (SameQ matching) with optional multiplicity control via n->{elems}
DeleteElements[list, {e1, e2, …}]
DeleteElements[list, n -> {e1, e2, …}]
DeleteElements[list, {n1, n2, …} -> {e1, e2, …}]
DeleteElements[{2, x, 1, x, a, y, x}, {x, y}]
→ {2, 1, a}DeleteElements[{2, x, 1, x, a, y, x}, 2 -> {x}]
→ {2, 1, a, y, x}DeleteElements[{2, x, 1, x, a, y, x}, {1, 2} -> {x, y}]
→ {2, 1, x, a, x}