modify withRunbookURL to allow internal annotation

[tristanburgess]

see https://github.com/grafana/deployment_tools/pull/118284

this PR allows a user of the withRunbookURL function to indicate that the internal_runbook_url annotation should be used instead of the runbook_url annotation.

[CLAassistant]

All committers have signed the CLA.

[Duologic]

Adding conditional like this is a bit of anti pattern that leads to overloading a function signature to satisfy every user.

I'd suggest giving the original default like this, it'll allow the same override but needs less maintenance if someone follows a slightly alternative annotation approach.

Suggested change

	withRunbookURL(url_format, groups, internal=false)::
	withRunbookURL(url_format, groups, annotation_key='runbook_url')::

Perhaps also add a line of documentation above this function to explain it.

[tristanburgess]

updated and tested

tk diff ksonnet/environments/ruler-exporter/main.jsonnet --name environments/ruler-exporter/dev-us-central-0

...
     ---
-    alert: UnhealthyComponents
+    alert: "UnhealthyComponents"
     annotations:
-      message: Unhealthy Flow components detected.
+      custom_runbook_annotation_key: "https://github.com/grafana/cloud-onboarding/blob/main/runbooks/HostedExporters-Agent.md#AgentUnhealthyComponents"
+      message: "Unhealthy Flow components detected."
     expr: "sum(agent_component_controller_running_components{health_type!=\"healthy\"}) > 0"
-    for: 15m
+    for: "15m"