fix(regexp): fix typo in E888 error message (#30161)

Co-authored-by: Eisuke Kawashima <e-kwsm@users.noreply.github.com>
(cherry picked from commit 3bcd5624be)

src/nvim/regexp.c

@@ -10006,7 +10006,7 @@ static int nfa_regatom(void)
     case 'e':
       EMIT(NFA_ZEND);
       rex.nfa_has_zend = true;
-      if (!re_mult_next("\\zs")) {
+      if (!re_mult_next("\\ze")) {
         return false;
       }
       break;