Added/updated snippets for docs (#2318)

docs/doc_examples/b3a711c3deddcdb8a3f6623184a8b794.asciidoc

@@ -0,0 +1,18 @@
+// 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.update({
+  index: "test",
+  id: 1,
+  script: {
+    source: "ctx._source.counter += params.count",
+    lang: "painless",
+    params: {
+      count: 4,
+    },
+  },
+});
+console.log(response);
+----