Added ChannelMessageSendEmbedWithMessage (#335)

* Added ChannelMessageSendEmbedWithMessage

* Updates ChannelMessageSendEmbed to use ChannelMessageSendEmbedWithMessage

restapi.go

@@ -1317,13 +1317,23 @@ func (s *Session) ChannelMessageSendTTS(channelID string, content string) (st *M
 // channelID : The ID of a Channel.
 // embed     : The embed data to send.
 func (s *Session) ChannelMessageSendEmbed(channelID string, embed *MessageEmbed) (st *Message, err error) {
+
+	return s.ChannelMessageSendEmbedWithMessage(channelID, "", embed)
+}
+
+// ChannelMessageSendEmbedWithMessage sends a message to the given channel with embedded data (bot only) and a message.
+// channelID : The ID of a Channel.
+// content   : The message to send.
+// embed     : The embed data to send.
+func (s *Session) ChannelMessageSendEmbedWithMessage(channelID string, content string, embed *MessageEmbed) (st *Message, err error) {
 	if embed != nil && embed.Type == "" {
 		embed.Type = "rich"
 	}
 
 	data := struct {
-		Embed *MessageEmbed `json:"embed"`
-	}{embed}
+		Embed   *MessageEmbed `json:"embed"`
+		Content string        `json:"content"`
+	}{embed, content}
 
 	// Send the message to the given channel
 	response, err := s.RequestWithBucketID("POST", EndpointChannelMessages(channelID), data, EndpointChannelMessages(channelID))