bug#23867: 25.1.50; Doc string containing `\N'

[Paul Eggert]

> Is it too difficult for \N followed by anything other than { to be
> treated (possibly with a warning?) as before (ie, not as an escape)?

It could be done, but I'd rather not. lread.c doesn't warn about other 
stuff, by and large, and any warnings are likely to be ignored anyway. 
It would be additional complexity for very little benefit.

As a general rule Elisp code should not use \X unless \X is documented 
to be part of an escape sequence, or X is an ASCII punctuation character 
that might otherwise confuse Emacs. (By the way, are the punctuation 
characters still an issue? I've forgotten what their problem was or is.)