Selecting an Outline Item from the Outline view informs via callback the
corresponding Destination that has been selected. This will be used to
move the application to the corresponding page/section/etc.
This is a nice addition to the outline view, which previously simply
displayed the titles of each section. Pages are shown in the first
column, but the tree is expanded via the second column, where the title
is.
This follows the same idea that Andreas was doing in this latest videos,
where construction-time TRY()s were not present but should have been.
Like Andreas did, moving the initialisation of such fields to the
factory function, which then returns ErrorOr solves the issue.
Most of the models were just calling did_update anyway, which is
pointless since it can be unified to the base Model class. Instead, code
calling update() will now call invalidate(), which functions identically
and is more obvious in what it does.
Additionally, a default implementation is provided, which removes the
need to add empty implementations of update() for each model subclass.
Co-Authored-By: Ali Mohammad Pur <ali.mpfard@gmail.com>
