This change allows us to substitute values into our rules files.
Example:
- alert: my_region_is_down
expr: up{region="{{ $my_region }}"} == 0
To support this change, rule annotations that used the expansion
{{ $labels.foo }} had to be surrounded with "{{` ... `}}" to render
correctly.
Change-Id: Ia7ac891de8261acca62105a3e2636bd747a5fbea
fb7fc87d23