Update rest-api-spec (#4942)

Co-authored-by: pquentin <42327+pquentin@users.noreply.github.com>

Author: github-actions[bot]

output/schema/validation-errors.json

@@ -255,12 +255,6 @@
       ],
       "response": []
     },
-    "reindex": {
-      "request": [
-        "Request: query parameter 'require_alias' does not exist in the json spec"
-      ],
-      "response": []
-    },
     "searchable_snapshots.clear_cache": {
       "request": [
         "Request: missing json spec query parameter 'index'"

specification/_json_spec/reindex.json

@@ -55,6 +55,11 @@
       "max_docs": {
         "type": "number",
         "description": "Maximum number of documents to process (default: all documents)"
+      },
+      "require_alias": {
+        "type": "boolean",
+        "default": false,
+        "description": "When true, requires destination to be an alias."
       }
     },
     "body": {