fancy-joiner

Fancy Joiner helps you join (and split) lines of text or code in
intelligent ways. It's particularly well-suited for shell-script-mode
and org-mode.

As you join or split lines in shell-script-mode, Fancy Joiner automatically
adds or removes semicolons as needed, among other tricks.

For all the details, please do see the README

Open it easily with:
  (find-file-read-only "README.org")   <--- C-x C-e here¹

or from any buffer:
  M-x fancy-joiner-see-readme

or read it online:
  <https://flandrew.srht.site/listful/sw-emacs-fancy-joiner.html>

¹ or the key that ‘eval-last-sexp’ is bound to, if not C-x C-e.