bug#55738: character escape bugs in the reader

[Mattias Engdegård]

Looks like there is code like

                     (setq bits (+ bits ?\C-\^@))

where the author wanted just the 'control' bit, and even

  (should (equal (kbd "C-RET") [?\C-\C-m]))

and while these are debatable in style (I'd prefer ?C-\0 to produce the control 
bit), the risk of breaking external code is too great.

Thus I'm scaling back ambitions a bit and have committed a much-reduced patch 
that just deals with the ?\LF part.