Add doc comment to VertexState

osu.Game.Rulesets.Catch/Edit/Blueprints/Components/VertexState.cs

@@ -7,12 +7,25 @@ using osu.Game.Rulesets.Catch.Objects;
 
 namespace osu.Game.Rulesets.Catch.Edit.Blueprints.Components
 {
+    /// <summary>
+    /// Holds the state of a vertex in the path of a <see cref="EditablePath"/>.
+    /// </summary>
     public class VertexState
     {
+        /// <summary>
+        /// Whether the vertex is selected.
+        /// </summary>
         public bool IsSelected { get; set; }
 
+        /// <summary>
+        /// Whether the vertex can be moved or deleted.
+        /// </summary>
         public bool IsFixed { get; set; }
 
+        /// <summary>
+        /// The position of the vertex before a vertex moving operation starts.
+        /// This is used to implement "memory-less" moving operations (only the final position matters) to improve UX.
+        /// </summary>
         public JuiceStreamPathVertex VertexBeforeChange { get; set; }
     }
 }