Change per-object endpoint to `/metrics/per-object`.

This conforms with other http endpoints.

deps/rabbitmq_prometheus/README.md

@@ -67,9 +67,9 @@ In order to not put unnecessary pressure on your metrics system, metrics are agg
 
 When debugging, it may be useful to return metrics per object (unaggregated).
 
-This can be done by scraping the `/metrics/per_object` endpoint:
+This can be done by scraping the `/metrics/per-object` endpoint:
 ```shell
-curl -v -H "Accept:text/plain" "http://localhost:15692/metrics/per_object"
+curl -v -H "Accept:text/plain" "http://localhost:15692/metrics/per-object"
 ```
 
 This can also be enabled as the default behavior of the `/metrics` endpoint on-the-fly,

deps/rabbitmq_prometheus/src/collectors/prometheus_rabbitmq_core_metrics_collector.erl

@@ -221,7 +221,7 @@ register() ->
 
 deregister_cleanup(_) -> ok.
 
-collect_mf(per_object, Callback) ->
+collect_mf('per-object', Callback) ->
     collect(true, Callback);
 collect_mf(_Registry, Callback) ->
     PerObjectMetrics = application:get_env(rabbitmq_prometheus, return_per_object_metrics, false),

deps/rabbitmq_prometheus/src/rabbit_prometheus_dispatcher.erl

@@ -14,7 +14,7 @@
 build_dispatcher() ->
     {ok, _} = application:ensure_all_started(prometheus),
     prometheus_registry:register_collectors([prometheus_rabbitmq_core_metrics_collector]),
-    prometheus_registry:register_collectors(per_object, [
+    prometheus_registry:register_collectors('per-object', [
         prometheus_vm_system_info_collector,
         prometheus_vm_dist_collector,
         prometheus_vm_memory_collector,

deps/rabbitmq_prometheus/src/rabbit_prometheus_handler.erl

@@ -32,7 +32,7 @@ is_authorized(ReqData, Context) ->
 
 setup() ->
     setup_metrics(telemetry_registry()),
-    setup_metrics(per_object).
+    setup_metrics('per-object').
 
 setup_metrics(Registry) ->
     ScrapeDuration = [{name, ?SCRAPE_DURATION},

deps/rabbitmq_prometheus/test/rabbit_prometheus_http_SUITE.erl

@@ -226,7 +226,7 @@ aggregated_metrics_test(Config) ->
     ?assertEqual(match, re:run(Body, "^rabbitmq_raft_entry_commit_latency_seconds ", [{capture, none}, multiline])).
 
 endpoint_per_object_metrics(Config) ->
-    per_object_metrics_test(Config, "/metrics/per_object").
+    per_object_metrics_test(Config, "/metrics/per-object").
 
 globally_configure_per_object_metrics_test(Config) ->
     per_object_metrics_test(Config, "/metrics").