patch 8.2.3977: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/eval.c b/src/eval.c
index f228067..99bc5a5 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -3936,7 +3936,7 @@
     if (len <= 0)
     {
 	if (verbose)
-	    emsg(_("E260: Missing name after ->"));
+	    emsg(_(e_missing_name_after_method));
 	ret = FAIL;
     }
     else