More flexible footer URLs for the category post widget plugin

For a long time, a user could get a link to the category archive page at the bottom of the widget. This simple patter was broken in the 4.7 release with the introduction of the “all categories” option which prompted the addition of a “manual” option to set the url of the link.

Reflecting on the feature, and how complex and strange the code ended being, we have decided to just get rid of the automation and let the user configure both the text and the URL. This is both because for the small price of extra 30 seconds of work the configuration ends being more readable, and it doesn’t make much sense to link to the category page, sending users to read again posts they already read while scanning the widget.

We did try to maintain backward compatibility, and if the url is missing we will try to automatically “guess” it, but it is a smart idea to retest widgets that use this feature.