Docs: Fix links to `default_template.go` in alert template reference file (#61340)

Docs: Fix links to `default_template.go` alert template reference file

docs/sources/alerting/fundamentals/alert-rules/message-templating.md

@@ -16,9 +16,9 @@ weight: 415
 
 # Message templating
 
-Notifications sent via contact points are built using messaging templates. Grafana's default templates are based on the [Go templating system](https://golang.org/pkg/text/template) where some fields are evaluated as text, while others are evaluated as HTML (which can affect escaping). The default template, defined in [default_template.go](https://github.com/grafana/grafana/blob/main/pkg/services/ngalert/notifier/channels/default_template.go), is a useful reference for custom templates.
+Notifications sent via contact points are built using messaging templates. Grafana's default templates are based on the [Go templating system](https://golang.org/pkg/text/template) where some fields are evaluated as text, while others are evaluated as HTML (which can affect escaping). The default template, defined in [default_template.go](https://github.com/grafana/alerting/blob/main/alerting/notifier/channels/default_template.go), is a useful reference for custom templates.
 
-Since most of the contact point fields can be templated, you can create reusable custom templates and use them in multiple contact points. The default template is defined in [default_template.go](https://github.com/grafana/grafana/blob/main/pkg/services/ngalert/notifier/channels/default_template.go) which can serve as a useful reference or starting point for custom templates.
+Since most of the contact point fields can be templated, you can create reusable custom templates and use them in multiple contact points. The default template is defined in [default_template.go](https://github.com/grafana/alerting/blob/main/alerting/notifier/channels/default_template.go) which can serve as a useful reference or starting point for custom templates.
 
 ### Using templates