Remove no longer relevant comments

osu.Game.Rulesets.Mania/Mods/ManiaModCover.cs

@@ -29,7 +29,6 @@ namespace osu.Game.Rulesets.Mania.Mods
 
         public override bool Ranked => false;
 
-        // Ideally we'd allow this, but it's not easy to handle due to the change in acronym from the base class.
         public override bool ValidForFreestyleAsRequiredMod => false;
 
         [SettingSource("Coverage", "The proportion of playfield height that notes will be hidden for.")]

osu.Game.Rulesets.Mania/Mods/ManiaModFadeIn.cs

@@ -14,8 +14,6 @@ namespace osu.Game.Rulesets.Mania.Mods
         public override string Acronym => "FI";
         public override LocalisableString Description => @"Keys appear out of nowhere!";
         public override double ScoreMultiplier => 1;
-
-        // Ideally we'd allow this, but it's not easy to handle due to the change in acronym from the base class.
         public override bool ValidForFreestyleAsRequiredMod => false;
 
         public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[]