Outputs inside a collapsed detail are computed only when it is opened: kit.js tells Shiny to
check again when it opens.
Examples
kit_detail("預覽", shiny::tags$p("前 10 列")) # "Preview", "First 10 rows"
#> <details class="kit-detail">
#> <summary>預覽</summary>
#> <div class="kit-detail-body">
#> <p>前 10 列</p>
#> </div>
#> </details>