Add ability to set custom text alert in Audio coach events

I have a long ride coming up, and it'd be nice to have alerts to remind me to consume calories/drink (since I tend to lose track of time and then forget!). Currently, the training manager seems only able to announce certain recorded items like distance, hr, etc. It would be nice to be able to have a custom variable "text" that I could put in.

Example:

Alert every 15 minutes: "Drink water!"

Alert every 45 minutes: "Eat something!"

etc.