Display name support for enum type converter (#2156)

* Display name support for enum type converter

* allow display attribute on enum type converter

* update docs/examples to include enum Display sample

* Revert "allow display attribute on enum type converter"

This reverts commit a0eec5b7555d366f9de7421f6fcf6bc71f2a4557.

* adds ChoiceDisplay for enum type converters

* Update EnumChoiceAttribute.cs

* fix renamed folder issue

* fix namespace

Co-authored-by: Xeno <eliotd@gmail.com>

src/Discord.Net.Interactions/Attributes/EnumChoiceAttribute.cs

@@ -0,0 +1,25 @@
+using System;
+
+namespace Discord.Interactions
+{
+    /// <summary>
+    ///     Customize the displayed value of a slash command choice enum. Only works with the default enum type converter.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Field, AllowMultiple = false, Inherited = true)]
+    public class ChoiceDisplayAttribute : Attribute
+    {
+        /// <summary>
+        ///     Gets the name of the parameter.
+        /// </summary>
+        public string Name { get; } = null;
+
+        /// <summary>
+        ///     Modify the default name and description values of a Slash Command parameter.
+        /// </summary>
+        /// <param name="name">Name of the parameter.</param>
+        public ChoiceDisplayAttribute(string name)
+        {
+            Name = name;
+        }
+    }
+}

src/Discord.Net.Interactions/TypeConverters/EnumConverter.cs

@@ -2,6 +2,7 @@ using Discord.WebSocket;
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using System.Threading.Tasks;
 
 namespace Discord.Interactions
@@ -27,12 +28,14 @@ namespace Discord.Interactions
                 var choices = new List<ApplicationCommandOptionChoiceProperties>();
 
                 foreach (var member in members)
+                {
+                    var displayValue = member.GetCustomAttribute<ChoiceDisplayAttribute>()?.Name ?? member.Name;
                     choices.Add(new ApplicationCommandOptionChoiceProperties
                     {
-                        Name = member.Name,
+                        Name = displayValue,
                         Value = member.Name
                     });
-
+                }
                 properties.Choices = choices;
             }
         }