patch 8.2.3975: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move more error messages to errors.h.
diff --git a/src/clientserver.c b/src/clientserver.c
index 2d234f2..2fefcc4 100644
--- a/src/clientserver.c
+++ b/src/clientserver.c
@@ -709,7 +709,7 @@
     make_connection();
     if (X_DISPLAY == NULL)
     {
-	emsg(_("E240: No connection to the X server"));
+	emsg(_(e_no_connection_to_x_server));
 	return FAIL;
     }
     return OK;
@@ -759,7 +759,7 @@
 	    vim_free(r);
 	}
 	else
-	    semsg(_("E241: Unable to send to %s"), server_name);
+	    semsg(_(e_unable_to_send_to_str), server_name);
 	return;
     }
 
@@ -1016,7 +1016,7 @@
 
     if (serverSendReply(server, reply) < 0)
     {
-	emsg(_("E258: Unable to send to client"));
+	emsg(_(e_unable_to_send_to_client));
 	return;
     }
     rettv->vval.v_number = 0;