Added/updated snippets for docs (#2318)

docs/doc_examples/0eae571e9e1c40a40cb4b1c9530a8987.asciidoc

@@ -0,0 +1,11 @@
+// This file is autogenerated, DO NOT EDIT
+// Use `node scripts/generate-docs-examples.js` to generate the docs examples
+
+[source, js]
+----
+const response = await client.ilm.migrateToDataTiers({
+  legacy_template_to_delete: "global-template",
+  node_attribute: "custom_attribute_name",
+});
+console.log(response);
+----