change name to Splice and use leverage vaargs to write

slice.go

@@ -593,15 +593,8 @@ func IsSortedByKey[T any, K constraints.Ordered](collection []T, iteratee func(i
 	return true
 }
 
-// Insert inserts an element at index i.
-// Play: https://go.dev/play/p/Eu3pk6_ODVQ
-func Insert[T any](collection []T, i int, element T) []T {
-	return append(collection[:i], append([]T{element}, collection[i:]...)...)
-}
-
-// InsertSlice inserts multiple elements at index i.
-// Play: https://go.dev/play/p/8gXdkTovsIC
-func InsertSlice[T any](collection []T, i int, elements []T) []T {
+// Play: https://go.dev/play/p/G5_GhkeSUBA
+func Splice[T any](collection []T, i int, elements ...T) []T {
 	if i < 0 || i > len(collection) {
 		panic("index out of bounds")
 	}

slice_test.go

@@ -760,24 +760,13 @@ func TestIsSortedByKey(t *testing.T) {
 	}))
 }
 
-func TestInsert(t *testing.T) {
-	t.Parallel()
-	is := assert.New(t)
-
-	inserts := Insert([]string{"a", "c", "d"}, 1, "b")
-	is.True(len(inserts) == 4 && inserts[1] == "b")
-
-	inserti := Insert([]int{1, 3, 4}, 1, 2)
-	is.True(len(inserti) == 4 && inserti[1] == 2)
-}
-
 func TestInsertSlice(t *testing.T) {
 	t.Parallel()
 	is := assert.New(t)
 
-	inserts := InsertSlice([]string{"a", "d"}, 1, []string{"b", "c"})
+	inserts := Splice([]string{"a", "d"}, 1, "b", "c")
 	is.True(len(inserts) == 4 && inserts[1] == "b" && inserts[2] == "c")
 
-	inserti := InsertSlice([]int{1, 4}, 1, []int{2, 3})
+	inserti := Splice([]int{1, 4}, 1, 2, 3)
 	is.True(len(inserti) == 4 && inserti[1] == 2 && inserti[2] == 3)
 }