style: lower case in descriptions

apps/emqx_modules/i18n/emqx_topic_metrics_api_i18n.conf

@@ -1,7 +1,7 @@
 emqx_topic_metrics_api {
   get_topic_metrics_api {
     desc {
-      en: """List Topic metrics"""
+      en: """List topic metrics"""
       zh: """获取主题监控数据"""
     }
   }
@@ -15,21 +15,21 @@ emqx_topic_metrics_api {
 
   post_topic_metrics_api {
     desc {
-      en: """Create Topic metrics"""
+      en: """Create topic metrics"""
       zh: """创建主题监控数据"""
     }
   }
 
   gat_topic_metrics_data_api {
     desc {
-      en: """Get Topic metrics"""
+      en: """Get topic metrics"""
       zh: """获取主题监控数据"""
     }
   }
 
   delete_topic_metrics_data_api {
     desc {
-      en: """Delete Topic metrics"""
+      en: """Delete topic metrics"""
       zh: """删除主题监控数据"""
     }
   }
@@ -43,7 +43,7 @@ emqx_topic_metrics_api {
 
   topic_metrics_api_response400 {
     desc {
-      en: """Bad Request. Already exists or bad topic name"""
+      en: """Bad request. Already exists or bad topic name"""
       zh: """错误请求。已存在或错误的主题名称"""
     }
   }