feat: implicit anchors for snake_case headers

Markdown headers style guide:

# Page title doesn't need an anchor
## All other headers need an explicit anchor {: #explicit_anchor }
## snake_case_headers_have_implicit_anchors

Мотивация данного патча в том чтобы в !361 (merged) не писать дублирующийся текст

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• Target branch: main
• Changes should be cherry-picked to 24.1: no