Review: Use HelpName (falling back to Name since HelpName is nullable)

Author: samblackburn

src/System.CommandLine/LocalizationResources.cs

@@ -54,8 +54,10 @@ internal static string InvalidCharactersInFileName(char invalidChar) =>
         /// </summary>
         internal static string RequiredArgumentMissing(ArgumentResult argumentResult) =>
             argumentResult.Parent is CommandResult commandResult
-                ? GetResourceString(Properties.Resources.CommandRequiredArgumentMissing, argumentResult.Argument.Name, commandResult.IdentifierToken.Value)
-                : RequiredArgumentMissing((OptionResult)argumentResult.Parent!);
+                ? GetResourceString(Properties.Resources.CommandRequiredArgumentMissing,
+                    argumentResult.Argument.HelpName ?? argumentResult.Argument.Name,
+                    commandResult.IdentifierToken.Value)
+                : RequiredArgumentMissing((OptionResult) argumentResult.Parent!);
 
         /// <summary>
         ///   Interpolates values into a localized string similar to Required argument missing for option: {0}.