on-call notifications for ios is outdated

[JordanSussman]

Documentation Page

https://docs.datadoghq.com/incident_response/on-call/guides/configure-mobile-device-for-on-call/?tab=ios#telephony-channels-voice-calls-and-sms

Issue Description

The on-call notifications on iOS has moved from Settings > Preferences > On-Call to Settings → Notifications → On-Call. Additionally, the screenshot is referencing the old UI.

[ethan-howes]

I've submitted two PRs to address this:

• Typo fix ("Ringstone" → "Ringtone"): <LINK>
• Navigation path fix (Settings > Notifications > On-Call): <LINK>

Note: the screenshot may still need updating internally.