Add chat type documentation

Author: ilyakaznacheev

types.go

@@ -104,17 +104,38 @@ type ChatPhoto struct {
 
 // Chat contains information about the place a message was sent.
 type Chat struct {
-	ID                  int64      `json:"id"`
-	Type                string     `json:"type"`
-	Title               string     `json:"title"`                          // optional
-	UserName            string     `json:"username"`                       // optional
-	FirstName           string     `json:"first_name"`                     // optional
-	LastName            string     `json:"last_name"`                      // optional
-	AllMembersAreAdmins bool       `json:"all_members_are_administrators"` // optional
-	Photo               *ChatPhoto `json:"photo"`
-	Description         string     `json:"description,omitempty"` // optional
-	InviteLink          string     `json:"invite_link,omitempty"` // optional
-	PinnedMessage       *Message   `json:"pinned_message"`        // optional
+	// ID is a unique identifier for this chat
+	ID int64 `json:"id"`
+	// Type of chat, can be either “private”, “group”, “supergroup” or “channel”
+	Type string `json:"type"`
+	// Title for supergroups, channels and group chats
+	// optional
+	Title string `json:"title"`
+	// UserName for private chats, supergroups and channels if available
+	// optional
+	UserName string `json:"username"`
+	// FirstName of the other party in a private chat
+	// optional
+	FirstName string `json:"first_name"`
+	// LastName of the other party in a private chat
+	// optional
+	LastName string `json:"last_name"`
+	// AllMembersAreAdmins
+	// optional
+	AllMembersAreAdmins bool `json:"all_members_are_administrators"`
+	// Photo is a chat photo
+	Photo *ChatPhoto `json:"photo"`
+	// Description for groups, supergroups and channel chats
+	// optional
+	Description string `json:"description,omitempty"`
+	// InviteLink is a chat invite link, for groups, supergroups and channel chats.
+	// Each administrator in a chat generates their own invite links,
+	// so the bot must first generate the link using exportChatInviteLink
+	// optional
+	InviteLink string `json:"invite_link,omitempty"`
+	// PinnedMessage Pinned message, for groups, supergroups and channels
+	// optional
+	PinnedMessage *Message `json:"pinned_message"`
 }
 
 // IsPrivate returns if the Chat is a private conversation.