Add new "Unknown" check-in status to Crons monitor details docs

[gaprl]

DESCRIBE YOUR PR

Renames the job monitoring page to monitor details and adds a new description for the "Unknown" check-in status. These updates are required for https://github.com/getsentry/sentry/pull/81012.

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• [ ] Checked Vercel preview for correctness, including links
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Name	Status	Preview	Comments	Updated (UTC)
sentry-docs	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Nov 20, 2024 9:45pm

2 Skipped Deployments

| Name | Status | Preview | Comments | Updated (UTC) | | :--- | :----- | :------ | :------- | :------ | | **changelog** | ⬜️ Ignored ([Inspect](https://vercel.com/sentry/changelog/EG6ac3PrEqVokGkCWJWZUGJ16fAu)) | | | Nov 20, 2024 9:45pm | | **develop-docs** | ⬜️ Ignored ([Inspect](https://vercel.com/sentry/develop-docs/J2DrcuKwHS7aHBfxn1ecMtGuEt5Z)) | | | Nov 20, 2024 9:45pm |

[codecov[bot]]

Bundle Report

Changes will increase total bundle size by 65 bytes (0.0%) :arrow_up:. This is within the configured threshold :white_check_mark:

Detailed changes

| Bundle name | Size | Change | | ----------- | ---- | ------ | | sentry-docs-server-cjs | 10.28MB | 6 bytes (-0.0%) :arrow_down: | | sentry-docs-edge-server-array-push | 363.93kB | 77 bytes (0.02%) :arrow_up: | | sentry-docs-client-array-push | 9.29MB | 6 bytes (-0.0%) :arrow_down: |

[gaprl]

Closing in favor of https://github.com/getsentry/sentry-docs/pull/11896