doc: add A53 (ignore resource deletion) to xds features

doc/grpc_xds_features.md

@@ -71,6 +71,7 @@ Aggregate Cluster Behavior Fixes | [A75](https://github.com/grpc/proposal/blob/m
 [Authorization (RBAC)](https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/filters/http/rbac/v3/rbac.proto):<br><ul><li>`LOG` action has no effect<li>CEL unsupported and rejected</ul> | [A41](https://github.com/grpc/proposal/blob/master/A41-xds-rbac.md) | v1.51.0<br>(C++ and Python) | v1.42.0 | 1.42.0 | |
 [Least Request LB Policy](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/upstream/load_balancing/load_balancers.html#weighted-least-request) | [A48](https://github.com/grpc/proposal/blob/master/A48-xds-least-request-lb-policy.md) |  | v1.48.0 |  |  |
 [Outlier Detection](https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/upstream/outlier):<br>Only the following detection types are supported:<ul><li>Success Rate</li><li>Failure Percentage</li></ul> | [A50](https://github.com/grpc/proposal/blob/master/A50-xds-outlier-detection.md) | v1.51.0 | v1.49.0 | v1.50.0 | v1.7.0 |
+Ignore Resource Deletion | [A53](https://github.com/grpc/proposal/blob/master/A53-xds-ignore-resource-deletion.md) | v1.48.0 | v1.48.0 | v1.55.0 | |
 [Custom Load Balancer Configuration](https://github.com/envoyproxy/envoy/blob/57be3189ffa3372b34e9480d1f02b2d165e49077/api/envoy/config/cluster/v3/cluster.proto#L1208) | [A52](https://github.com/grpc/proposal/blob/master/A52-xds-custom-lb-policies.md) | v1.55.0 | v1.47.0 | v1.56.0 | v1.10.0 |
 [xDS Federation](https://github.com/cncf/xds/blob/main/proposals/TP1-xds-transport-next.md) | [A47](https://github.com/grpc/proposal/blob/master/A47-xds-federation.md) | v1.55.0 | v1.55.0 | v1.55.0 | |
 [Client-Side Weighted Round Robin LB Policy](https://github.com/envoyproxy/envoy/blob/a6d46b6ac4750720eec9a49abe701f0df9bf8e0a/api/envoy/extensions/load_balancing_policies/client_side_weighted_round_robin/v3/client_side_weighted_round_robin.proto#L36) | [A58](https://github.com/grpc/proposal/blob/master/A58-client-side-weighted-round-robin-lb-policy.md) | v1.55.0 | v1.54.0 | v1.56.0 | |