Fix typo and migration description

Emby.Server.Implementations/Localization/LocalizationManager.cs

@@ -194,7 +194,7 @@ namespace Emby.Server.Implementations.Localization
                 ratings.Add(new ParentalRating("Approved", 0));
             }
 
-            // Matches PG (this has differnet age restrictions depending on country)
+            // Matches PG (this has different age restrictions depending on country)
             if (!ratings.Any(x => x.Value == 10))
             {
                 ratings.Add(new ParentalRating("10", 10));

Jellyfin.Server/Migrations/Routines/MigrateRatingLevels.cs

@@ -9,7 +9,7 @@ using SQLitePCL.pretty;
 namespace Jellyfin.Server.Migrations.Routines
 {
     /// <summary>
-    /// Remove duplicate entries which were caused by a bug where a file was considered to be an "Extra" to itself.
+    /// Migrate rating levels to new rating level system.
     /// </summary>
     internal class MigrateRatingLevels : IMigrationRoutine
     {