Add translation: "閉じる"

locales/ja/common.json

@@ -3,5 +3,6 @@
     "source": "ソースコード",
     "tos": "yude.jp サービス利用規約",
     "yes_playing": "{{playing}} をプレイ中",
-    "listening": "{{listening}} を再生中"
+    "listening": "{{listening}} を再生中",
+    "close": "閉じる"
 }