Log Message:
ikiwiki: update to 3.20250221. Changes:

* po.pm: fixes for po4a >= 0.70.
* CGI::printheader: optional HTTP status argument
* comments: return HTTP 202 for moderated comments
* page.tmpl: don't generate an empty parentlinks span
* new plugins:
  * Jason Blevins' h1title plugin (previously external/contrib)
  * DuckDuckGo plugin for site searching
* new theme: lightdark. Supports browse preferences for light or
  dark mode.
* Default html5 to '1'
* Remove charset attribute from forms
* Use the HTML5 details tag for more backlinks
* Remove extra quote character from date spans
* t/po.t: Add missing PO header
* admonitions plugin