Add exception to core.get to handle index_not_found & document not found (#2156)

* Add exception to core.get to handle index_not_found & document not found

* add documentation to get exception

Author: Anaethelion

output/schema/schema.json

@@ -18,7 +18,17 @@
  */
 
 import { GetResult } from '@global/get/types'
+import { ErrorResponseBase } from '@_types/Base'
 
 export class Response<TDocument> {
   body: GetResult<TDocument>
+  exceptions: [
+    {
+      // Special case exception for 404 status code, Elasticsearch will return either:
+      //  * index_not_found_exception as an error if the index doesn't exist
+      //  * GetResult with only the requested _id, _index properties and found as a false boolean
+      statusCodes: [404]
+      body: GetResult<TDocument> | ErrorResponseBase
+    }
+  ]
 }