Do I understand that all of the above applies only to Slack? Props to melori.arellano for taking the time, and did a good job of documenting the templating for Slack. In the forums. But this 79 posts five-month back-and-forth topic needs to be consolidated and put into documentation.
What about the sixteen (16) OTHER Contact Point types that AM supposedly supports? Where is the documentation for those, Grafana? And why do 16 different CP’s have different ways of templating? 
You are asking people who need to send to multiple CPs to learn different syntax for each one.
If Grafana does not document HOW to configure for the other Contact Points, including which code to put into which Alert field or Template field, it seems to me that it only theoretically supports them. In practical terms, Grafana does not, in truth, support them, and is padding the numbers of supported platforms, and wasting a lot of users time.