patch 8.2.3959: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more errors to errors.h.
diff --git a/src/ex_getln.c b/src/ex_getln.c
index b4316d8..814681b 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -4390,7 +4390,7 @@
     if (!win_valid(old_curwin) || !bufref_valid(&old_curbuf))
     {
 	cmdwin_result = Ctrl_C;
-	emsg(_("E199: Active window or buffer deleted"));
+	emsg(_(e_active_window_or_buffer_deleted));
     }
     else
     {