patch 8.2.3986: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/netbeans.c b/src/netbeans.c
index 00be244..5bdb868 100644
--- a/src/netbeans.c
+++ b/src/netbeans.c
@@ -2515,7 +2515,7 @@
 
     if (NETBEANS_OPEN)
     {
-	emsg(_("E511: netbeans already connected"));
+	emsg(_(e_netbeans_already_connected));
 	return;
     }
 
@@ -3481,7 +3481,7 @@
 	char msgbuf[IOSIZE];
 
 	vim_snprintf(msgbuf, IOSIZE,
-		       _("E505: %s is read-only (add ! to override)"), IObuff);
+		       _(e_is_read_only_add_bang_to_override), IObuff);
 	nbdebug(("    %s\n", msgbuf));
 	emsg(msgbuf);
     }