fix broken link (argoproj#16722)

Signed-off-by: Noam Gal <[email protected]>

docs/operator-manual/notifications/triggers.md

@@ -1,7 +1,7 @@
 The trigger defines the condition when the notification should be sent. The definition includes name, condition
 and notification templates reference. The condition is a predicate expression that returns true if the notification
 should be sent. The trigger condition evaluation is powered by [antonmedv/expr](https://github.com/antonmedv/expr).
-The condition language syntax is described at [Language-Definition.md](https://github.com/antonmedv/expr/blob/master/docs/Language-Definition.md).
+The condition language syntax is described at [language-definition.md](https://github.com/antonmedv/expr/blob/master/docs/language-definition.md).
 
 The trigger is configured in the `argocd-notifications-cm` ConfigMap. For example the following trigger sends a notification
 when application sync status changes to `Unknown` using the `app-sync-status` template: