GitLab

(rectangle): New group.
(rectangle--pos-cols): Add `window' argument.
(rectangle--string-preview-state, rectangle--string-preview-window):
New vars.
(rectangle--string-flush-preview, rectangle--string-erase-preview)
(rectangle--space-to, rectangle--string-preview): New functions.
(string-rectangle): Use them.
(rectangle--inhibit-region-highlight): New var.
(rectangle--highlight-for-redisplay): Obey it.  Make sure
`apply-on-region' uses the point-crutches of the right window.
Use :align-to rather than multiple spaces.