Update bulk.asciidoc (#1752)

Fix typo

Author: nkwwk

docs/examples/bulk.asciidoc

@@ -77,8 +77,8 @@ async function run () {
           // fix the document before to try it again.
           status: action[operation].status,
           error: action[operation].error,
-          operation: body[i * 2],
-          document: body[i * 2 + 1]
+          operation: operations[i * 2],
+          document: operations[i * 2 + 1]
         })
       }
     })