Allusion is the type of figurative language used here, I believe.
The Alchemist concludes with Santiago at the end of his journey across the sea and sands, back to where he started, dreaming under a sycamore tree. That is until the last line of the novel, "I'm coming, Fatima..." (Epilogue.13); This line shows that Santiago's journey is not yet done and that he will continue to travel even after the end of the novel.
