patch 8.2.3190: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move error messages to errors.h and give them a clear name.
diff --git a/src/ex_cmds2.c b/src/ex_cmds2.c
index 04859ad..15560d8 100644
--- a/src/ex_cmds2.c
+++ b/src/ex_cmds2.c
@@ -413,7 +413,7 @@
 {
     if (curbuf->b_ffname == NULL)
     {
-	emsg(_(e_noname));
+	emsg(_(e_no_file_name));
 	return FAIL;
     }
     return OK;