Defines a pinned layout along a single axis (horizontal or vertical). Used with (and by) the Pinned
layout widget. In most cases, it's easiest to think of a Pin as defining the position of the starting
and ending edges of the child. So, for a horizontal Pin, start maps to left, and end maps to right.
Pinned attempts to fill as much space as is available, and position its child within
that space based on specified edge positions. It mirrors the Adobe XD responsive layout
model, but can be used independently.
Please see the README for additional information and examples.
