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 #12045)
diff --git a/src/edit.c b/src/edit.c
index a030e53..ff9fc0e 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -3527,6 +3527,10 @@
 		  dont_sync_undo = MAYBE;
 		  break;
 
+	case ESC:
+		  // Esc after CTRL-G cancels it.
+		  break;
+
 	// Unknown CTRL-G command, reserved for future expansion.
 	default:  vim_beep(BO_CTRLG);
     }