Merge branch 'kyozm/proper-lack-of-permission-messages' into 'master'

proper message on permission check failure  for commands

Closes #303

See merge request veloren/veloren!592

server/src/cmd.rs

@@ -61,8 +61,9 @@ impl ChatCommand {
             if !server.entity_is_admin(entity) {
                 server.clients.notify(
                     entity,
-                    ServerMsg::private(String::from(
+                    ServerMsg::private(format!(
-                        "Unavailable command '/{}'.\nType '/help' for available commands",
+                        "You don't have permission to use '/{}'.",
+                        self.keyword
                     )),
                 );
                 return;