Add wait_for_completion to snapshot.delete (#4875) (#4878)

(cherry picked from commit 0543299)

# Conflicts:
#	output/schema/schema.json

Author: pquentin

output/openapi/elasticsearch-openapi.json

@@ -305,12 +305,6 @@
       ],
       "response": []
     },
-    "snapshot.delete": {
-      "request": [
-        "Request: missing json spec query parameter 'wait_for_completion'"
-      ],
-      "response": []
-    },
     "snapshot.repository_analyze": {
       "request": [
         "Request: query parameter 'register_operation_count' does not exist in the json spec"

output/schema/schema.json

@@ -42,5 +42,11 @@ export interface Request extends RequestBase {
   }
   query_parameters: {
     master_timeout?: Duration
+    /**
+     * If `true`, the request returns a response when the matching snapshots are all deleted.
+     * If `false`, the request returns a response as soon as the deletes are scheduled.
+     * @server_default true
+     */
+    wait_for_completion?: boolean
   }
 }