add convert extension functions for Sequence

[anatawa12]

please add functions shown below:

/**
 * Returns an immutable list containing all elements of this collection.
 */
fun <T> Sequence<T>.toImmutableList(): ImmutableList<T> = toPersistentList()

/**
 * Returns a persistent list containing all elements of this collection.
 */
fun <T> Sequence<T>.toPersistentList(): PersistentList<T> = persistentListOf<T>() + this

/**
 * Returns an immutable set of all elements of this collection.
 */
fun <T> Sequence<T>.toImmutableSet(): ImmutableSet<T> = toPersistentSet()

/**
 * Returns a persistent set of all elements of this collection.
 */
fun <T> Sequence<T>.toPersistentSet(): PersistentSet<T> = persistentSetOf<T>() + this

[qurbonzoda]

Fixed in master.
Thanks!