Add get_similar_documents code-sample

Author: ellnix

.code-samples.meilisearch.yaml

@@ -751,3 +751,5 @@ get_all_batches_1: |-
   client.get_batches()
 get_batch_1: |-
   client.get_batch(BATCH_UID)
+get_similar_post_1: |-
+  client.index("INDEX_NAME").get_similar_documents({"id": "TARGET_DOCUMENT_ID", "embedder": "default"})