MM-11008: Fix translation and change the code to be auto-extracted (#9009)

app/channel.go

@@ -397,13 +397,13 @@ func (a *App) UpdateChannelPrivacy(oldChannel *model.Channel, user *model.User)
 }
 
 func (a *App) postChannelPrivacyMessage(user *model.User, channel *model.Channel) *model.AppError {
-	privacy := (map[string]string{
+	message := (map[string]string{
-		model.CHANNEL_OPEN:    "private_to_public",
+		model.CHANNEL_OPEN:    utils.T("api.channel.change_channel_privacy.private_to_public"),
-		model.CHANNEL_PRIVATE: "public_to_private",
+		model.CHANNEL_PRIVATE: utils.T("api.channel.change_channel_privacy.public_to_private"),
 	})[channel.Type]
 	post := &model.Post{
 		ChannelId: channel.Id,
-		Message:   utils.T("api.channel.change_channel_privacy." + privacy),
+		Message:   message,
 		Type:      model.POST_CHANGE_CHANNEL_PRIVACY,
 		UserId:    user.Id,
 		Props: model.StringInterface{

i18n/en.json

@@ -99,6 +99,14 @@
     "id": "api.channel.add_user_to_channel.type.app_error",
     "translation": "Can not add user to this channel type"
   },
+  {
+    "id": "api.channel.change_channel_privacy.private_to_public",
+    "translation": "This channel has been converted to a Public Channel and can be joined by any team member."
+  },
+  {
+    "id": "api.channel.change_channel_privacy.public_to_private",
+    "translation": "This channel has been converted to a Private Channel."
+  },
   {
     "id": "api.channel.convert_channel_to_private.default_channel_error",
     "translation": "This default channel cannot be converted into a private channel."