Translate remaining ButtonSystem strings and rename to match class name

osu.Game/Localisation/ButtonSystemStrings.cs

@@ -0,0 +1,44 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Localisation;
+
+namespace osu.Game.Localisation
+{
+    public static class ButtonSystemStrings
+    {
+        private const string prefix = @"osu.Game.Localisation.ButtonSystem";
+
+        /// <summary>
+        /// "solo"
+        /// </summary>
+        public static LocalisableString Solo => new TranslatableString(getKey(@"solo"), @"solo");
+
+        /// <summary>
+        /// "multi"
+        /// </summary>
+        public static LocalisableString Multi => new TranslatableString(getKey(@"multi"), @"multi");
+
+        /// <summary>
+        /// "playlists"
+        /// </summary>
+        public static LocalisableString Playlists => new TranslatableString(getKey(@"playlists"), @"playlists");
+
+        /// <summary>
+        /// "play"
+        /// </summary>
+        public static LocalisableString Play => new TranslatableString(getKey(@"play"), @"play");
+
+        /// <summary>
+        /// "edit"
+        /// </summary>
+        public static LocalisableString Edit => new TranslatableString(getKey(@"edit"), @"edit");
+
+        /// <summary>
+        /// "browse"
+        /// </summary>
+        public static LocalisableString Browse => new TranslatableString(getKey(@"browse"), @"browse");
+
+        private static string getKey(string key) => $@"{prefix}:{key}";
+    }
+}