Format a document publication date for display.
Returns an HTML string like
<span class="doc-date"><strong>Published:</strong> <time datetime="2026-03-04">2026-03-04</time></span>
using the localized "Published" label, or empty string if datum is missing.
Format a document publication date for display. Returns an HTML string like
<span class="doc-date"><strong>Published:</strong> <time datetime="2026-03-04">2026-03-04</time></span>using the localized "Published" label, or empty string if datum is missing.