feature: Global interaction post execution event. (#2213)

* Init

* Variable set to event

* Put internal above private

* Revert "Put internal above private"

This reverts commit 77784f001f.

* Revert "Variable set to event"

This reverts commit 2b0cb81d76.

* Revert "Init"

This reverts commit 9892ce7b51.

* Potentially improved approach

src/Discord.Net.Interactions/InteractionService.cs

@@ -24,6 +24,29 @@ namespace Discord.Interactions
         public event Func<LogMessage, Task> Log { add { _logEvent.Add(value); } remove { _logEvent.Remove(value); } }
         internal readonly AsyncEvent<Func<LogMessage, Task>> _logEvent = new ();
 
+        /// <summary>
+        ///     Occurs when any type of interaction is executed.
+        /// </summary>
+        public event Func<ICommandInfo, IInteractionContext, IResult, Task> InteractionExecuted
+        {
+            add
+            {
+                SlashCommandExecuted += value;
+                ContextCommandExecuted += value;
+                ComponentCommandExecuted += value;
+                AutocompleteCommandExecuted += value;
+                ModalCommandExecuted += value;
+            }
+            remove
+            {
+                SlashCommandExecuted -= value;
+                ContextCommandExecuted -= value;
+                ComponentCommandExecuted -= value;
+                AutocompleteCommandExecuted -= value;
+                ModalCommandExecuted -= value;
+            }
+        }
+
         /// <summary>
         ///     Occurs when a Slash Command is executed.
         /// </summary>