Add documentation

Author: daneden

Sources/Types+List.swift

@@ -30,9 +30,10 @@ public struct List: Codable, Identifiable {
 }
 
 extension List: Fielded {
+  /// Additional fields that can be requested on the ``List`` object
   public typealias Field = PartialKeyPath<Self>
 
-  static func fieldName(field: PartialKeyPath<List>) -> String? {
+  static internal func fieldName(field: PartialKeyPath<List>) -> String? {
     switch field {
     case \.createdAt: return "created_at"
     case \.description: return "description"
@@ -44,11 +45,13 @@ extension List: Fielded {
     }
   }
 
-  static var fieldParameterName = "list.fields"
+  static internal var fieldParameterName = "list.fields"
 }
 
 extension List: Expandable {
+  /// Fields that can be expanded on the ``List`` type
   public enum Expansions: Expansion {
+    /// The User object for the list’s owner
     case ownerId(fields: Set<User.Field>)
 
     internal var rawValue: String {
@@ -69,7 +72,9 @@ extension List: Expandable {
 }
 
 extension List {
+  /// Expanded objects included alongside the ``List``
   public struct Includes: Codable {
+    /// The users expanded with this List. Since ``List.Expansions`` contains only `ownerId`, this will  contain the expanded owner User object.
     public let users: [User]?
   }
 }

Sources/Types+Media.swift

@@ -84,6 +84,7 @@ extension Media {
 }
 
 extension Media: Fielded {
+  /// Additional fields that can be requested on the ``Media`` object
   public typealias Field = PartialKeyPath<Self>
 
   static internal func fieldName(field: PartialKeyPath<Media>) -> String? {
@@ -106,13 +107,15 @@ extension Media: Fielded {
 }
 
 extension Media {
+  /// Valid mime types for media that can be uploaded and attached to a Tweet
   public enum MimeType: String {
     case jpeg = "image/jpeg"
     case png = "image/png"
     case gif = "image/gif"
     case mov = "video/mov"
     case mp4 = "video/mp4"
 
+    /// The associated media category for a given mime type
     var mediaCategory: String {
       switch self {
       case .jpeg, .png: