Make reducer builder closure parameters explicit (#1897)

- Scope(...:child:)
  - forEach(...:element:)

The one exception is `CombineReducers`, which already includes the
`Reducers` in its name.

Author: stephencelis

Sources/ComposableArchitecture/Reducer/Reducers/ForEachReducer.swift

@@ -53,7 +53,7 @@ extension ReducerProtocol {
   public func forEach<ElementState, ElementAction, ID: Hashable, Element: ReducerProtocol>(
     _ toElementsState: WritableKeyPath<State, IdentifiedArray<ID, ElementState>>,
     action toElementAction: CasePath<Action, (ID, ElementAction)>,
-    @ReducerBuilder<ElementState, ElementAction> _ element: () -> Element,
+    @ReducerBuilder<ElementState, ElementAction> element: () -> Element,
     file: StaticString = #file,
     fileID: StaticString = #fileID,
     line: UInt = #line

Sources/ComposableArchitecture/Reducer/Reducers/Scope.swift

@@ -146,7 +146,7 @@ public struct Scope<ParentState, ParentAction, Child: ReducerProtocol>: ReducerP
   public init<ChildState, ChildAction>(
     state toChildState: WritableKeyPath<ParentState, ChildState>,
     action toChildAction: CasePath<ParentAction, ChildAction>,
-    @ReducerBuilder<ChildState, ChildAction> _ child: () -> Child
+    @ReducerBuilder<ChildState, ChildAction> child: () -> Child
   ) where ChildState == Child.State, ChildAction == Child.Action {
     self.init(
       toChildState: .keyPath(toChildState),
@@ -218,7 +218,7 @@ public struct Scope<ParentState, ParentAction, Child: ReducerProtocol>: ReducerP
   public init<ChildState, ChildAction>(
     state toChildState: CasePath<ParentState, ChildState>,
     action toChildAction: CasePath<ParentAction, ChildAction>,
-    @ReducerBuilder<ChildState, ChildAction> _ child: () -> Child,
+    @ReducerBuilder<ChildState, ChildAction> child: () -> Child,
     file: StaticString = #file,
     fileID: StaticString = #fileID,
     line: UInt = #line