In my custom module
amap, I have
amap.routing.yml with (among others) this route:
amap.distribution_inscription_many_form: path: '/amap/editPlanningMany' defaults: _form: '\Drupal\amap\Form\DistributionInscriptionManyForm' _title: 'Update Planning' requirements: _permission: 'edit distribution inscription entities'
I'd like to have a link in the title of the route, something like
Update Planning <a href="/amap/editPlanningOne">Click here</a>
Drupal 8 API documentation says in Structure of routes
_title: The page title for the route. It may differ from the menu link title.
_title_arguments: Additional arguments for the title text passed along to t().
_title_context: Additional context information for the title text passed along to t().
_title_callback: A PHP callable (typically classname::method) returning the page title for the route.
but I don't know how to use it...
How can I do that?