Change of Lisp syntax for "fancy" quotes in Emacs 27?

[Noam Postavsky]

In Emacs 26 and earlier the following is valid lisp code:

(setq ’bar 42)
(setq foo ’bar)

In the current master branch, this will signal (invalid-read-syntax
"strange quote" "’"). To write the equivalent the ’ must be backslash
escaped:

(setq \’bar 42)
(setq foo \’bar)

(the backslash escaping also works in earlier Emacs versions).

The point of this change is to give a more straightforward error in
cases where a plain straight quote is accidentally written instead of
a curved one.

In Bug#30217, Drew Adams strongly objects to this change. I don't want
to "sneak" this in, so I'm asking here for people's thoughts on this.

References:
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=30217
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=2967

PS In case anyone has trouble reading the example code (e.g., due to
some email encoding failure), evaluating

   (insert "(setq \u2019bar 42)\n(setq foo \u2019bar)")

will write it into your current buffer.