feat: implement IEquatable for UVCoord

- Add IEquatable<UVCoord> implementation to UVCoord struct.
- Override `Equals(object)` and add `Equals(UVCoord)` for equality checks.
- Override `GetHashCode` using U and V coordinates.

Signed-off-by: Illustar0 <me@illustar0.com>

Author: Illustar0

components/RangeSelector/src/RangeSelector.Helpers.UVCoord.cs

@@ -8,7 +8,7 @@ namespace CommunityToolkit.WinUI.Controls;
 /// A struct representing a coordinate in UV adjusted space.
 /// </summary>
 [DebuggerDisplay("({U}u,{V}v)")]
-public struct UVCoord
+public struct UVCoord: IEquatable<UVCoord>
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="UVCoord"/> struct.
@@ -127,4 +127,19 @@ public double V
     {
         return !(measure1 == measure2);
     }
+
+    public override bool Equals(object obj)
+    {
+        return obj is UVCoord other && Equals(other);
+    }
+
+    public bool Equals(UVCoord other)
+    {
+        return this == other;
+    }
+
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(U, V);
+    }
 }