feat: use <time> tag (#34131)

app/javascript/mastodon/components/formatted_date.tsx

@@ -0,0 +1,26 @@
+import type { ComponentProps } from 'react';
+
+import { FormattedDate } from 'react-intl';
+
+export const FormattedDateWrapper = (
+  props: ComponentProps<typeof FormattedDate> & { className?: string },
+) => (
+  <FormattedDate {...props}>
+    {(date) => (
+      <time dateTime={tryIsoString(props.value)} className={props.className}>
+        {date}
+      </time>
+    )}
+  </FormattedDate>
+);
+
+const tryIsoString = (date?: string | number | Date): string => {
+  if (!date) {
+    return '';
+  }
+  try {
+    return new Date(date).toISOString();
+  } catch {
+    return date.toString();
+  }
+};