add/remove/change fields, tweak the validation code for the fields, etc. It
will not validate or display the form.
-Form validation and display can be overridden by the formbuilder hook.
-By default, ikiwiki will do a basic validation and display of the form,
-but if this hook is registered, it will stop that and let the hook take
-over.
+Just before a form is displayed to the user, the `formbuilder` hook is
+called. It can be used to validate the form, but should not display it.
### savestate
When pages are deleted, ikiwiki automatically deletes their pagestate too.
+Note that page state does not persist across wiki rebuilds, only across
+wiki updates.
+
### Other variables
If your plugin needs to access data about other pages in the wiki. It can