chore: clarify validator parameter

Author: nanotaboada

src/Dotnet.Samples.AspNetCore.WebApi/Validators/PlayerRequestModelValidator.cs

@@ -4,21 +4,30 @@
 
 namespace Dotnet.Samples.AspNetCore.WebApi.Validators;
 
+/// <summary>
+/// Validator for PlayerRequestModel.
+/// This class uses FluentValidation to define validation rules for the
+/// PlayerRequestModel.
+/// </summary>
+/// <remarks>
+/// This class is part of the FluentValidation library, which provides a fluent
+/// interface for building validation rules.
+/// </remarks>
 public class PlayerRequestModelValidator : AbstractValidator<PlayerRequestModel>
 {
     public PlayerRequestModelValidator()
     {
-        RuleFor(x => x.FirstName).NotEmpty().WithMessage("FirstName is required.");
+        RuleFor(player => player.FirstName).NotEmpty().WithMessage("FirstName is required.");
 
-        RuleFor(x => x.LastName).NotEmpty().WithMessage("LastName is required.");
+        RuleFor(player => player.LastName).NotEmpty().WithMessage("LastName is required.");
 
-        RuleFor(x => x.SquadNumber)
+        RuleFor(player => player.SquadNumber)
             .NotEmpty()
             .WithMessage("SquadNumber is required.")
             .GreaterThan(0)
             .WithMessage("SquadNumber must be greater than 0.");
 
-        RuleFor(x => x.AbbrPosition)
+        RuleFor(player => player.AbbrPosition)
             .NotEmpty()
             .WithMessage("AbbrPosition is required.")
             .Must(Position.IsValidAbbr)