feat: Adds documentation and removes some unused code.

Sources/ComposableSubscriber/ReceiveAction.swift

@@ -1,9 +1,20 @@
 import ComposableArchitecture
 
+/// An action type that exposes a `receive` method that accepts task result, generally from
+/// calling external dependencies.  
+///
+/// This allows for multiple receive actions to be nested under
+/// one single action that handle the `failure` and `success` cases more conveniently
+/// by using some of the higher order reducers provided by this package.
 public protocol ReceiveAction<ReceiveAction> {
+
+  /// The success cases.
   associatedtype ReceiveAction
+
+  /// The root receive case that is used to handle the results.
   static func receive(_ result: TaskResult<ReceiveAction>) -> Self
 
+  /// Extracts the result from the action.
   var result: TaskResult<ReceiveAction>? { get }
 }