Added/updated snippets for docs (#2318)

docs/doc_examples/21d0ab6e420bfe7a1639db6af5b2e9c0.asciidoc

@@ -0,0 +1,35 @@
+// 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.search({
+  index: "reviews",
+  filter_path: "aggregations",
+  size: 0,
+  runtime_mappings: {
+    "rating.out_of_ten": {
+      type: "long",
+      script: {
+        source: "emit(doc['rating'].value * params.scaleFactor)",
+        params: {
+          scaleFactor: 2,
+        },
+      },
+    },
+  },
+  aggs: {
+    review_average: {
+      avg: {
+        field: "rating.out_of_ten",
+      },
+    },
+    review_variability: {
+      median_absolute_deviation: {
+        field: "rating.out_of_ten",
+      },
+    },
+  },
+});
+console.log(response);
+----