include last_close in the response formats table

Attribute exists in the example request and should be included in the table below.

content/references/rippled-api/public-rippled-methods/server-info-methods/server_state.md

@@ -538,6 +538,7 @@ The `state` object may have some arrangement of the following fields:
 | `closed_ledger`                  | Object          | _(May be omitted)_ Information on the most recently closed ledger that has not been validated by consensus. If the most recently validated ledger is available, the response omits this field and includes `validated_ledger` instead. The member fields are the same as the `validated_ledger` field. |
 | `io_latency_ms`                  | Number          | Amount of time spent waiting for I/O operations, in milliseconds. If this number is not very, very low, then the `rippled` server is probably having serious load issues. |
 | `jq_trans_overflow`              | String - Number | The number of times this server has had over 250 transactions waiting to be processed at once. A large number here may mean that your server is unable to handle the transaction load of the XRP Ledger network. For detailed recommendations of future-proof server specifications, see [Capacity Planning](capacity-planning.html). [New in: rippled 0.90.0][] |
+| `last_close`                     | Object          | Information about the last time the server closed a ledger, including the amount of time it took to reach a consensus and the number of trusted validators participating. |
 | `load`                           | Object          | _(Admin only)_ Detailed information about the current load state of the server. |
 | `load.job_types`                 | Array           | _(Admin only)_ Information about the rate of different types of jobs the server is doing and how much time it spends on each. |
 | `load.threads`                   | Number          | _(Admin only)_ The number of threads in the server's main job pool. |