A reminder the user should know before pressing a button. It is not a result, so it has no shadow. At most one per section; if it can go in the status box, don't add a separate callout; if there is a button, put the button outside the box.
Examples
kit_callout("外部連結不適用:這一回合只有一個世代,這不是錯誤。")
#> <div class="kit-callout">外部連結不適用:這一回合只有一個世代,這不是錯誤。</div>
# "External linking does not apply: this round has only one cohort. This is not an error."
kit_callout("資料裡有疑似遺漏值代碼,建議先到「遺漏值處理」。", warn = TRUE)
#> <div class="kit-callout kit-callout-warn">資料裡有疑似遺漏值代碼,建議先到「遺漏值處理」。</div>
# "The data seem to contain missing-value codes; go to 'Missing values' first."