Added/updated snippets for docs (#2318)

docs/doc_examples/451e7c29b2cf738cfc822f7c175bef56.asciidoc

@@ -0,0 +1,21 @@
+// 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.indices.putIndexTemplate({
+  name: "my-index-template",
+  index_patterns: ["my-data-stream*"],
+  data_stream: {},
+  priority: 500,
+  template: {
+    lifecycle: {
+      data_retention: "7d",
+    },
+  },
+  _meta: {
+    description: "Template with data stream lifecycle",
+  },
+});
+console.log(response);
+----