[Bug c/121739] Unicode character constants are not allowed to have multiple characters in C23

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121739

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Hmm, 

<source>: In function 'main':
<source>:2:5: warning: multi-character literal cannot have an encoding prefix
    2 |     u'ab';
      |     ^~~~~