chore: fix spell && style error

examples/gateway.lwm2m.conf.example

@@ -34,4 +34,4 @@ gateway.lwm2m {
     }
     update_msg_publish_condition = always
     xml_dir = "/etc/emqx/lwm2m_xml"
-}
+}

examples/plugin.conf.example

@@ -24,4 +24,4 @@ plugin {
 
     ## The installation directory for the external plugins
     install_dir = "plugins"
-}
+}

examples/prometheus.conf.example

@@ -25,4 +25,4 @@ prometheus {
 
     ## set true to enable this
     enable = false
-}
+}

examples/rpc-with-ssl.conf.example

@@ -73,4 +73,4 @@ rpc {
 
     ## Socket buffer size in user mode
     socket_buffer = 1MB
- }
+}

examples/rpc-with-tcp.conf.example

@@ -64,4 +64,4 @@ rpc {
 
     ## Socket buffer size in user mode
     socket_buffer = 1MB
- }
+}

examples/slow_subs.conf.example

@@ -25,4 +25,4 @@ slow_subs {
 
     ## use true to enable this
     enable = false
-}
+}