patch 8.2.4010: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 01bd3b4..ede0f20 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -2679,7 +2679,7 @@
 {
     if (allbuf_lock > 0)
     {
-	emsg(_("E811: Not allowed to change buffer information now"));
+	emsg(_(e_not_allowed_to_change_buffer_information_now));
 	return TRUE;
     }
     return FALSE;