Update alerting docs to reflect new terminology

[bmorelli25]

What?

Renamed Alerts -> Rules and Actions -> Connectors in UI

Why?

• Terminology issue: New alerting terminology kibana#90375
• Implementation PR: [Alerting] Update UI to reflect new terminology kibana#93597

Where?

• APM app docs
• Observability docs

[EamonnTP]

@brandon Maybe this work is still-in-progress? On the edge-oblt cluster I'm seeing a mismatch in terminology within the Obs apps.

When you select Alerts (which I think should be Rules?), you can see Create rule.

And Actions hasn't been updated to Connectors.

[bmorelli25]

Sorry, my copy/pasta description is confusing. Based on the definitions in elastic/kibana#90375 (comment), I think this is correct. Rules and actions are subtypes of alerts.

[EamonnTP]

Perfect. Do you mind if I pick this one up?

[bmorelli25]

Sounds good. At least the APM team has some enhancements planned for alerts, so I would hold off until after FF before getting started.

[EamonnTP]

Closed by #679 and elastic/kibana#104232