Support alerts over number charts

[benjreinhart]

I have a count of errors. I would like to define a threshold and alert on it but it seems alerting isn't supported for numbers. This will be particularly useful when rates are supported as I will put an error rate as a number and want to alert if it hits a certain threshold.

Alert on line/bar chart

None for number

[brandon-pereira]

Thanks for reaching out @benjreinhart! that is a great idea! We are definitely open to this feature being introduced.