This built-in emacs library actually provides a data structure that
can work as an LRU list through the existing helper function to move
an element to the front of the ring if it already exists.
As a result, the code for workspace history moving becomes a lot less
brittle and complicated than it was before. No more carefully figuring
out when to modify state, just push it in the ring unless it's being
rotated already.
Change-Id: If354e0618fc5a6d7333776468eec077596cfe9df
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9162
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI