Fix and add comments

osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/Data/MonoEncoding.cs

@@ -26,6 +26,9 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour.Data
         /// </summary>
         public int Index;
 
+        /// <summary>
+        /// How long the mono pattern encoded within is
+        /// </summary>
         public int RunLength => EncodedData.Count;
     }
 }

osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/Colour/TaikoColourDifficultyPreprocessor.cs

@@ -30,12 +30,9 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour
             {
                 coupledEncoding.Payload[0].Payload[0].EncodedData[0].Colour.CoupledColourEncoding = coupledEncoding;
 
-                // TODO: Review this -
                 // The outermost loop is kept a ForEach loop since it doesn't need index information, and we want to
                 // keep i and j for ColourEncoding's and MonoEncoding's index respectively, to keep it in line with
                 // documentation.
-                // If we want uniformity for the outermost loop, it can be switched to a for loop with h or something
-                // else as an index
                 //
                 // While parent and index should be part of the encoding process, they are assigned here instead due to
                 // this being a simple one location to assign them.

osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/TaikoDifficultyHitObject.cs

@@ -17,9 +17,24 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing
     /// </summary>
     public class TaikoDifficultyHitObject : DifficultyHitObject
     {
+        /// <summary>
+        /// The list of all <see cref="TaikoDifficultyHitObject"/> of the same colour as this <see cref="TaikoDifficultyHitObject"/> in the beatmap.
+        /// </summary>
         private readonly IReadOnlyList<TaikoDifficultyHitObject>? monoDifficultyHitObjects;
+
+        /// <summary>
+        /// The index of this <see cref="TaikoDifficultyHitObject"/> in <see cref="monoDifficultyHitObjects"/>.
+        /// </summary>
         public readonly int MonoIndex;
+
+        /// <summary>
+        /// The list of all <see cref="TaikoDifficultyHitObject"/> that is either a regular note or finisher in the beatmap
+        /// </summary>
         private readonly IReadOnlyList<TaikoDifficultyHitObject> noteDifficultyHitObjects;
+
+        /// <summary>
+        /// The index of this <see cref="TaikoDifficultyHitObject"/> in <see cref="noteDifficultyHitObjects"/>.
+        /// </summary>
         public readonly int NoteIndex;
 
         /// <summary>