documentation update

Core/Collections/MapPoint.cs

@@ -1,5 +1,7 @@
 namespace Just.Core.Collections;
 
+/// <summary>A value and its coordinates within a <see cref="IMap{T}"/>.</summary>
+/// <typeparam name="T">The type of the map element.</typeparam>
 public readonly struct MapPoint<T>(T value, int x, int y, IMap<T> map)
 {
     public readonly T Value = value;