When streaming API is disconnected, poll home/notifications (#2776)

* When streaming API is disconnected, poll home/notifications
Display slightly different empty home timeline message if user is following others
Cull notifications to 20 items when over 40 get added in real-time
Run manage:translations

* Optimize <HomeTimeline /> a little

app/javascript/mastodon/locales/zh-CN.json

@@ -23,6 +23,7 @@
   "column.mutes": "被静音的用户",
   "column.notifications": "通知",
   "column.public": "跨站公共时间轴",
+  "column_back_button.label": "Back",
   "column_subheading.navigation": "导航",
   "column_subheading.settings": "设置",
   "compose_form.lock_disclaimer": "你的账户没 {locked}. 任何人可以通过关注你来查看只有关注者可见的嘟文.",
@@ -33,7 +34,6 @@
   "compose_form.sensitive": "将媒体文件标示为“敏感内容”",
   "compose_form.spoiler": "将部分文本藏于警告消息之后",
   "compose_form.spoiler_placeholder": "敏感内容的警告消息",
-  "emoji_button.label": "加入表情符号",
   "confirmation_modal.cancel": "取消",
   "confirmations.block.confirm": "屏蔽",
   "confirmations.block.message": "想好了，真的要屏蔽 {name}?",
@@ -44,6 +44,7 @@
   "emoji_button.activity": "活动",
   "emoji_button.flags": "旗帜",
   "emoji_button.food": "食物和饮料",
+  "emoji_button.label": "加入表情符号",
   "emoji_button.nature": "自然",
   "emoji_button.objects": "物体",
   "emoji_button.people": "人物",
@@ -53,6 +54,7 @@
   "empty_column.community": "本站时间轴暂时未有内容，快贴文来抢头香啊！",
   "empty_column.hashtag": "这个标签暂时未有内容。",
   "empty_column.home": "你还没有关注任何用户。快看看{public}，向其他用户搭讪吧。",
+  "empty_column.home.inactivity": "Your home feed is empty. If you have been inactive for a while, it will be regenerated for you soon.",
   "empty_column.home.public_timeline": "公共时间轴",
   "empty_column.notifications": "你没有任何通知纪录，快向其他用户搭讪吧。",
   "empty_column.public": "跨站公共时间轴暂时没有内容！快写一些公共的嘟文，或者关注另一些服务站的用户吧！你和本站、友站的交流，将决定这里出现的内容。",
@@ -129,8 +131,8 @@
   "report.submit": "提交",
   "report.target": "Reporting",
   "search.placeholder": "搜索",
+  "search_results.total": "{count, number} {count, plural, one {result} other {results}}",
   "status.cannot_reblog": "没法转嘟这条嘟文啦……",
-  "search.status_by": "按{name}搜索嘟文",
   "status.delete": "删除",
   "status.favourite": "赞",
   "status.load_more": "加载更多",