feat!: support for arbitrary objects as indices

BREAKING-CHANGE: Many external and internal functions have been renamed
to replace the word "number" with the more general word "index."

README.org

@@ -19,14 +19,13 @@
 - [[#future-developments][Future developments]]
 
 * Introduction
-Window numbers for Emacs: Navigate your windows and frames using numbers !
 
-This package is an extended and actively maintained version of the
-[[https://github.com/nschum/window-numbering.el][window-numbering]] package by Nikolaj Schumacher, with some ideas and code taken
-from [[https://github.com/abo-abo/ace-window][ace-window]].
+This package is a fork of the [[https://github.com/deb0ch/emacs-winum][winum]] package, which is itself a fork of the
+[[https://github.com/nschum/window-numbering.el][window-numbering]] package.
 
-This version brings, among other things, support for number sets across multiple
-frames, giving the user a smoother experience of multi-screen Emacs.
+Compared to winum, this fork adds support for windows having arbitrary Lisp values
+as identifiers, as opposed to strictly increasing numbers. The public
+API is largely the same, however, and simple numbers are still the default.
 
 * Changelog
 ** Sep. 11 2019