[8.16] What's new in 8.16 (backport #6077)

[mergify]

Resolves #5953.

Preview: What’s new in 8.16

---

This is an automatic backport of pull request #6077 done by Mergify.

[mergify]

Cherry-pick of 411ac24 has failed:

On branch mergify/bp/8.16/pr-6077
Your branch is up to date with 'origin/8.16'.

You are currently cherry-picking commit 411ac24b.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	new file:   docs/whats-new/images/8.16/attck-disc-alerts-number-menu.png
	new file:   docs/whats-new/images/8.16/endpoint-protection-rules.png
	new file:   docs/whats-new/images/8.16/entities-section.png
	new file:   docs/whats-new/images/8.16/flyout-settings.gif
	new file:   docs/whats-new/images/8.16/install-enable-rules.png
	new file:   docs/whats-new/images/8.16/knowledge-base-add-index-config.png
	new file:   docs/whats-new/images/8.16/manual-rule-run-table.png
	new file:   docs/whats-new/images/8.16/new-note-alert-event.png
	new file:   docs/whats-new/images/8.16/recalc-ers.png
	new file:   docs/whats-new/images/8.16/visualize-tab-lp-alert-details.gif
	new file:   docs/whats-new/images/8.16/wiz-findings.png

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   docs/whats-new.asciidoc

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[github-actions]

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