Get notifications for complete Bits security investigations

[janine-c]

What does this PR do? What is the motivation?

Some small updates to document a new tag we added, which users can specify in their security notifications so they can get those sweet sweet Bits investigation verdicts.

Merge readiness

Will run past the PM for accuracy first before checking this box! Got approval, all good to go 😎

• Ready for merge

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AI assistance

Additional notes

[github-actions]

Preview links (active after the build_preview check completes)

Modified Files

• https://docs-staging.datadoghq.com/janine/security-notifications-bits-investigator-tag/bits_ai/bits_security_analyst
• https://docs-staging.datadoghq.com/janine/security-notifications-bits-investigator-tag/security/notifications/rules

[evazorro]

Minor wording suggestion, but looks good otherwise!