refactor: rename cluster_rpc_handler to cluster_rpc_cleaner

this reflects what is actually does

apps/emqx_conf/src/emqx_cluster_rpc_handler.erl

@@ -13,7 +13,9 @@
 %% See the License for the specific language governing permissions and
 %% limitations under the License.
 %%--------------------------------------------------------------------
--module(emqx_cluster_rpc_handler).
+
+%% @doc This module is responsible for cleaning up the cluster RPC MFA.
+-module(emqx_cluster_rpc_cleaner).
 
 -behaviour(gen_server).
 

apps/emqx_conf/src/emqx_conf_sup.erl

@@ -36,7 +36,7 @@ init([]) ->
     ChildSpecs =
         [
             child_spec(emqx_cluster_rpc, []),
-            child_spec(emqx_cluster_rpc_handler, [])
+            child_spec(emqx_cluster_rpc_cleaner, [])
         ],
     {ok, {SupFlags, ChildSpecs}}.