[V1][Metrics] Updated list of deprecated metrics in v0.8 (#14695)

Signed-off-by: Mark McLoughlin <markmc@redhat.com>

docs/source/serving/metrics.md

@@ -39,7 +39,16 @@ The following metrics are exposed:
 
 The following metrics are deprecated and due to be removed in a future version:
 
-- *(No metrics are currently deprecated)*
+- `vllm:num_requests_swapped`, `vllm:cpu_cache_usage_perc`, and
+  `vllm:cpu_prefix_cache_hit_rate` because KV cache offloading is not
+  used in V1.
+- `vllm:gpu_prefix_cache_hit_rate` is replaced by queries+hits
+  counters in V1.
+- `vllm:time_in_queue_requests` because it duplicates
+  `vllm:request_queue_time_seconds`.
+- `vllm:model_forward_time_milliseconds` and
+  `vllm:model_execute_time_milliseconds` because
+  prefill/decode/inference time metrics should be used instead.
 
 Note: when metrics are deprecated in version `X.Y`, they are hidden in version `X.Y+1`
 but can be re-enabled using the `--show-hidden-metrics-for-version=X.Y` escape hatch,