Tag Alias: letterbox ↔ letterboxed

Letterbox and letterboxed should be aliased in some fashion. I like letterboxed better, though letterbox has the majority use.

Went with letterboxed.

request for reverse tag alias letterboxed -> letterbox

reason: for uniformity and consistency with pillarbox and windowbox.

or new tag aliases too for pillarboxed and windowboxed, whichever the case might be appropriate. thanks.

*ed makes more sense imo.

Aliased to windowboxed and pillarboxed.