This is to give a default name to form controls by default, like <label>
does to <input> and <textarea> in HTML.
Had to add a “plain” version of the label, with neither the <u> tag used
in rich text or the ‘&’ in the “regular” label, otherwise orca would
spell out these symbols.
This is to accept Alt+(whatever has & in front in the label) for labels,
buttons, actions, and whatever requires a nmenonic.
I created an attached property because it is kind of similar to QML’s
Keys property.