Normalize translation key for user prefrerences

preferences normalized:
 - annotations
 - annotations_subscribed
 - automatic_instance_redirect
 - autoplay
 - captions
 - comments
 - continue
 - continue_autoplay
 - dark_mode
 - default_home
 - extend_desc
 - feed_menu
 - listen
 - local
 - locale
 - max_results
 - notifications_only
 - player_style
 - quality
 - quality_dash
 - related_videos
 - show_nick
 - sort
 - speed
 - thin_mode
 - unseen_only
 - video_loop
 - volume
 - vr_mode

locales/eu.json

@@ -58,20 +58,20 @@
     "E-mail": "E-posta",
     "Preferences": "Hobespenak",
     "Player preferences": "Erreproduzigailuaren hobespenak",
-    "Autoplay: ": "Automatikoki erreproduzitu: ",
-    "Autoplay next video: ": "Erreproduzitu automatikoki hurrengo bideoa: ",
-    "Preferred video quality: ": "Hobetsitako bideoaren kalitatea: ",
-    "Player volume: ": "Erreproduzigailuaren bolumena: ",
-    "Default comments: ": "Lehenetsitako iruzkinak: ",
+    "preferences_autoplay_label": "Automatikoki erreproduzitu: ",
+    "preferences_continue_autoplay_label": "Erreproduzitu automatikoki hurrengo bideoa: ",
+    "preferences_quality_label": "Hobetsitako bideoaren kalitatea: ",
+    "preferences_volume_label": "Erreproduzigailuaren bolumena: ",
+    "preferences_comments_label": "Lehenetsitako iruzkinak: ",
     "youtube": "YouTube",
     "reddit": "reddit",
-    "Default captions: ": "Lehenetsitako azpitituluak: ",
-    "Show related videos: ": "Erakutsi erlazionatutako bideoak: ",
-    "Show annotations by default: ": "Erakutsi oharrak modu lehenetsian: ",
+    "preferences_captions_label": "Lehenetsitako azpitituluak: ",
+    "preferences_related_videos_label": "Erakutsi erlazionatutako bideoak: ",
+    "preferences_annotations_label": "Erakutsi oharrak modu lehenetsian: ",
     "Visual preferences": "Hobespen bisualak",
-    "Player style: ": "Erreproduzigailu mota: ",
+    "preferences_player_style_label": "Erreproduzigailu mota: ",
     "Dark mode: ": "Gai iluna: ",
-    "Theme: ": "Gaia: ",
+    "preferences_dark_mode_label": "Gaia: ",
     "dark": "iluna",
     "light": "argia",
     "Subscription preferences": "Harpidetzen hobespenak"