breaking changes: widget 寫法更改/可添加非sticky區域widget

feat: 升級facebook comment js 到 v10
fix: 修復當內容過少時， footer 沒有底部靠攏的bug
improvement: 404頁面不再顯示 rightside

layout/includes/third-party/comments/waline.pug

@@ -13,7 +13,7 @@ script.
         emojiCDN: '#{theme.waline.emojiCDN}',
         emojiMaps: !{emojiMaps},
         visitor: #{theme.waline.visitor},
-        dark: '[data-theme="dark"]'
+        dark: 'html[data-theme="dark"]'
       }, !{JSON.stringify(theme.waline.option)}))
     }