Handle bulk errors in examples

docs/examples/bulk.asciidoc

@@ -12,7 +12,7 @@ const { Client } = require('@elastic/elasticsearch')
 const client = new Client({ node: 'http://localhost:9200' })
 
 async function run () {
-  await client.bulk({
+  const { body: bulkResponse } = await client.bulk({
     // here we are forcing an index refresh,
     // otherwise we will not get any result
     // in the consequent search
@@ -40,6 +40,11 @@ async function run () {
     ]
   })
 
+  if (bulkResponse.errors) {
+    console.log(bulkResponse)
+    process.exit(1)
+  }
+
   // Let's search!
   const { body } = await client.search({
     index: 'game-of-thrones',