rename WithIndex operator to Enumerate

pair.go

@@ -90,10 +90,10 @@ func RightOf[_ Pair[K, V], K, V any]() Operator[Pair[K, V], V] {
 	)
 }
 
-// WithIndex maps each value emitted by the source Observable to a Pair
-// containing two elements: the Key field stores the index of each value
-// starting from init; the Value field stores the value.
-func WithIndex[V any, K constraints.Integer](init K) Operator[V, Pair[K, V]] {
+// Enumerate maps each value emitted by the source Observable to a Pair
+// where the Key field stores the index of each value starting from init
+// and the Value field stores each value.
+func Enumerate[V any, K constraints.Integer](init K) Operator[V, Pair[K, V]] {
 	return NewOperator(
 		func(source Observable[V]) Observable[Pair[K, V]] {
 			return func(c Context, o Observer[Pair[K, V]]) {

pair_test.go

@@ -108,15 +108,15 @@ func TestWithIndex(t *testing.T) {
 	NewTestSuite[string](t).Case(
 		rx.Pipe3(
 			rx.Just("A", "B", "C"),
-			rx.WithIndex[string](1),
+			rx.Enumerate[string](1),
 			rx.Reduce(make(map[int]string), add),
 			ToString[map[int]string](),
 		),
 		"map[1:A 2:B 3:C]", ErrComplete,
 	).Case(
 		rx.Pipe3(
 			rx.Throw[string](ErrTest),
-			rx.WithIndex[string](1),
+			rx.Enumerate[string](1),
 			rx.Reduce(make(map[int]string), add),
 			ToString[map[int]string](),
 		),