Remove Auto-Injection

this should be handled by #520

src/Discord.Net.Commands/Attributes/InjectAttribute.cs

@@ -1,15 +0,0 @@
-using System;
-
-namespace Discord.Commands
-{
-    /// <summary>
-    /// Indicates that this property should be filled in by dependency injection.
-    /// </summary>
-    /// <remarks>
-    /// This property **MUST** have a setter.
-    /// </remarks>
-    [AttributeUsage(AttributeTargets.Property)]
-    public sealed class InjectAttribute : Attribute
-    {
-    }
-}

src/Discord.Net.Commands/Utilities/ReflectionUtils.cs

@@ -43,21 +43,6 @@ namespace Discord.Commands
                 try
                 {
                     T instance = (T)constructor.Invoke(args);
-                    var fields = instance.GetType().GetRuntimeProperties().Where(p => p.GetCustomAttribute<InjectAttribute>() != null).Where(p => p.CanWrite);
-                    foreach (var field in fields)
-                    {
-                        object arg;
-                        if (map == null || !map.TryGet(field.PropertyType, out arg))
-                        {
-                            if (field.PropertyType == typeof(CommandService))
-                                arg = service;
-                            else if (field.PropertyType == typeof(IDependencyMap))
-                                arg = map;
-                            else
-                                throw new InvalidOperationException($"Failed to inject \"{typeInfo.FullName}\", dependency \"{field.PropertyType.FullName}\" was not found.");
-                        }
-                        field.SetValue(instance, arg);
-                    }
                     return instance;
                 }
                 catch (Exception ex)