[SwiftRefactor] PackageManifest: Remove an outdated TODO that is no longer applicable

Author: xedin

Sources/SwiftRefactor/PackageManifest/AddPackageDependency.swift

@@ -26,9 +26,6 @@ public struct AddPackageDependency: ManifestEditRefactoringProvider {
 
   /// The set of argument labels that can occur after the "dependencies"
   /// argument in the Package initializers.
-  ///
-  /// TODO: Could we generate this from the the PackageDescription module, so
-  /// we don't have keep it up-to-date manually?
   private static let argumentLabelsAfterDependencies: Set<String> = [
     "targets",
     "swiftLanguageVersions",

Sources/SwiftRefactor/PackageManifest/AddPackageTarget.swift

@@ -28,9 +28,6 @@ public struct AddPackageTarget: ManifestEditRefactoringProvider {
 
   /// The set of argument labels that can occur after the "targets"
   /// argument in the Package initializers.
-  ///
-  /// TODO: Could we generate this from the the PackageDescription module, so
-  /// we don't have keep it up-to-date manually?
   private static let argumentLabelsAfterTargets: Set<String> = [
     "swiftLanguageVersions",
     "cLanguageStandard",

Sources/SwiftRefactor/PackageManifest/AddPluginUsage.swift

@@ -29,9 +29,6 @@ public struct AddPluginUsage: ManifestEditRefactoringProvider {
 
   /// The set of argument labels that can occur after the "plugins"
   /// argument in the Target initializers. (There aren't any right now)
-  ///
-  /// TODO: Could we generate this from the the PackageDescription module, so
-  /// we don't have keep it up-to-date manually?
   private static let argumentLabelsAfterPluginUsages: Set<String> = []
 
   /// Produce the set of source edits needed to add the given package

Sources/SwiftRefactor/PackageManifest/AddProduct.swift

@@ -25,9 +25,6 @@ public struct AddProduct: ManifestEditRefactoringProvider {
   }
   /// The set of argument labels that can occur after the "products"
   /// argument in the Package initializers.
-  ///
-  /// TODO: Could we generate this from the the PackageDescription module, so
-  /// we don't have keep it up-to-date manually?
   private static let argumentLabelsAfterProducts: Set<String> = [
     "dependencies",
     "targets",

Sources/SwiftRefactor/PackageManifest/AddTargetDependency.swift

@@ -31,9 +31,6 @@ public struct AddTargetDependency: ManifestEditRefactoringProvider {
 
   /// The set of argument labels that can occur after the "dependencies"
   /// argument in the various target initializers.
-  ///
-  /// TODO: Could we generate this from the the PackageDescription module, so
-  /// we don't have keep it up-to-date manually?
   private static let argumentLabelsAfterDependencies: Set<String> = [
     "path",
     "exclude",