vim-patch:9.1.0573: ex: no implicit print for single addresses

Problem:  ex: no implicit print for single addresses
Solution: explicitly print even during single addresses,
          as requested by POSIX (Mohamed Akram)

See the POSIX behaviour here:
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ex.html#tag_20_40_13_03
Section 6b

closes: vim/vim#15230

c25a7084e9

Co-authored-by: Mohamed Akram <mohd.akram@outlook.com>

src/nvim/ex_docmd.c

@@ -2079,6 +2079,7 @@ static char *do_one_cmd(char **cmdlinep, int flags, cstack_T *cstack, LineGetter
     if (ea.skip) {  // skip this if inside :if
       goto doend;
     }
+    assert(errormsg == NULL);
     errormsg = ex_range_without_command(&ea);
     goto doend;
   }
@@ -2431,7 +2432,7 @@ static char *ex_range_without_command(exarg_T *eap)
 {
   char *errormsg = NULL;
 
-  if (*eap->cmd == '|' || (exmode_active && eap->line1 != eap->line2)) {
+  if (*eap->cmd == '|' || exmode_active) {
     eap->cmdidx = CMD_print;
     eap->argt = EX_RANGE | EX_COUNT | EX_TRLBAR;
     if ((errormsg = invalid_range(eap)) == NULL) {

src/nvim/getchar.c

@@ -2729,7 +2729,7 @@ static int vgetorpeek(bool advance)
             timedout = true;
             continue;
           }
-          // In Ex-mode \n is compatible with original Vim behaviour.
+
           // For the command line only CTRL-C always breaks it.
           // For the cmdline window: Alternate between ESC and
           // CTRL-C: ESC for most situations and CTRL-C to close the