Remove FluentResults, documentation

PkmnLib.Static/Utils/Errors/OutOfRange.cs

@@ -1,14 +1,13 @@
-using FluentResults;
 
 namespace PkmnLib.Static.Utils.Errors;
 
 /// <summary>
 /// A result that indicates an index is out of range.
 /// </summary>
-public class OutOfRange : Error
+public class OutOfRangeException : Exception
 {
-    /// <inheritdoc cref="OutOfRange"/>
-    public OutOfRange(string hint, int index, int max)
+    /// <inheritdoc cref="OutOfRangeException"/>
+    public OutOfRangeException(string hint, int index, int max)
         : base($"{hint} index {index} is out of range. Must be between 0 and {max - 1}.")
     {
     }