Update Japanese translation

locales/ja.json

@@ -77,7 +77,7 @@
     "Fallback captions: ": "フォールバック時の字幕: ",
     "Show related videos: ": "関連動画を表示: ",
     "Show annotations by default: ": "デフォルトでアノテーションを表示: ",
-    "Automatically extend video description: ": "",
+    "Automatically extend video description: ": "動画の説明文を自動的に拡張: ",
     "Visual preferences": "外観設定",
     "Player style: ": "プレイヤースタイル: ",
     "Dark mode: ": "ダークモード: ",
@@ -157,8 +157,8 @@
     "Title": "タイトル",
     "Playlist privacy": "再生リストのプライバシー",
     "Editing playlist `x`": "再生リスト `x` を編集中",
-    "Show more": "",
-    "Show less": "",
+    "Show more": "表示を増やす",
+    "Show less": "表示を減らす",
     "Watch on YouTube": "YouTube で視聴",
     "Hide annotations": "アノテーションを隠す",
     "Show annotations": "アノテーションを表示",
@@ -387,11 +387,11 @@
     "Videos": "動画",
     "Playlists": "プレイリスト",
     "Community": "コミュニティ",
-    "relevance": "",
-    "rating": "",
+    "relevance": "関連",
+    "rating": "評価",
     "date": "",
     "views": "",
-    "content_type": "",
+    "content_type": "コンテンツの種類",
     "duration": "",
     "features": "",
     "sort": "",
@@ -402,7 +402,7 @@
     "year": "",
     "video": "",
     "channel": "",
-    "playlist": "",
+    "playlist": "再生リスト",
     "movie": "",
     "show": "",
     "hd": "",