fix typos

Author: Alex Ley

api.html.md.erb

@@ -454,7 +454,7 @@ The request provides these query string parameters as useful hints for brokers.
 <tr>
   <td>operation</td>
   <td>string</td>
-  <td>The field optionally returned by the service broker on Provision, Update, Deprovision asyn responses. Repesents any state the service broker responsed with as a URL encoded string.</a>.</td>
+  <td>The field optionally returned by the service broker on Provision, Update, Deprovision async responses. Repesents any state the service broker responsed with as a URL encoded string.</a>.</td>
 </tr>
 </tbody>
 </table>
@@ -702,7 +702,7 @@ For success responses, the following fields are supported. Others will be ignore
 <tr>
   <td>operation</td>
   <td>string</td>
-  <td>For async responses, service brokers can return operation state as a string. This field will be provided back to the service broker on `last_opertion` requests as a URL encoded query param.</a>.</td>
+  <td>For async responses, service brokers can return operation state as a string. This field will be provided back to the service broker on `last_operation` requests as a URL encoded query param.</a>.</td>
 </tr>
 </tboby>
 </table>
@@ -871,7 +871,7 @@ For success responses, the following fields are supported. Others will be ignore
 <tr>
   <td>operation</td>
   <td>string</td>
-  <td>For async responses, service brokers can return operation state as a string. This field will be provided back to the service broker on `last_opertion` requests as a URL encoded query param.</a>.</td>
+  <td>For async responses, service brokers can return operation state as a string. This field will be provided back to the service broker on `last_operation` requests as a URL encoded query param.</a>.</td>
 </tr>
 </tboby>
 </table>
@@ -1196,7 +1196,7 @@ For success responses, the following fields are supported. Others will be ignore
 <tr>
   <td>operation</td>
   <td>string</td>
-  <td>For async responses, service brokers can return operation state as a string. This field will be provided back to the service broker on `last_opertion` requests as a URL encoded query param.</a>.</td>
+  <td>For async responses, service brokers can return operation state as a string. This field will be provided back to the service broker on `last_operation` requests as a URL encoded query param.</a>.</td>
 </tr>
 </tboby>
 </table>