vim-patch:9.0.1354: "gr CTRL-G" stays in virtual replace mode

Problem:    "gr CTRL-G" stays in virtual replace mode. (Pierre Ganty)
Solution:   Prepend CTRL-V before control characters. (closes vim/vim#12045)

d6a4ea3aa0

Cherry-pick Test_edit_gr_special() from patch 9.0.1347.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/edit.c

@@ -3444,6 +3444,10 @@ static void ins_ctrl_g(void)
     dont_sync_undo = kNone;
     break;
 
+  case ESC:
+    // Esc after CTRL-G cancels it.
+    break;
+
   // Unknown CTRL-G command, reserved for future expansion.
   default:
     vim_beep(BO_CTRLG);