Change the minimum length of slash commands to 1 (#284)

* Change the minimum length of slash commands to 1. This is the correct value according to the docs and it has been changed after user feedback.

* Fix the limit in 3 other places

Co-authored-by: quin lynch <lynchquin@gmail.com>

src/Discord.Net.Core/Entities/Interactions/ContextMenus/MessageCommandBuilder.cs

@@ -19,7 +19,7 @@ namespace Discord
             set
             {
                 Preconditions.NotNullOrEmpty(value, nameof(Name));
-                Preconditions.AtLeast(value.Length, 3, nameof(Name));
+                Preconditions.AtLeast(value.Length, 1, nameof(Name));
                 Preconditions.AtMost(value.Length, MaxNameLength, nameof(Name));
 
                 _name = value;

src/Discord.Net.Core/Entities/Interactions/ContextMenus/UserCommandBuilder.cs

@@ -19,7 +19,7 @@ namespace Discord
             set
             {
                 Preconditions.NotNullOrEmpty(value, nameof(Name));
-                Preconditions.AtLeast(value.Length, 3, nameof(Name));
+                Preconditions.AtLeast(value.Length, 1, nameof(Name));
                 Preconditions.AtMost(value.Length, MaxNameLength, nameof(Name));
 
                 _name = value;

src/Discord.Net.Rest/DiscordRestApiClient.cs

@@ -1187,7 +1187,7 @@ namespace Discord.API
         {
             Preconditions.NotNull(command, nameof(command));
             Preconditions.AtMost(command.Name.Length, 32, nameof(command.Name));
-            Preconditions.AtLeast(command.Name.Length, 3, nameof(command.Name));
+            Preconditions.AtLeast(command.Name.Length, 1, nameof(command.Name));
 
             if (command.Type == ApplicationCommandType.Slash)
             {
@@ -1258,7 +1258,7 @@ namespace Discord.API
         {
             Preconditions.NotNull(command, nameof(command));
             Preconditions.AtMost(command.Name.Length, 32, nameof(command.Name));
-            Preconditions.AtLeast(command.Name.Length, 3, nameof(command.Name));
+            Preconditions.AtLeast(command.Name.Length, 1, nameof(command.Name));
 
             if (command.Type == ApplicationCommandType.Slash)
             {