const-ref tokens in loop since they aren't modified here

src/jlog/shared/jlog.cpp

@@ -58,7 +58,7 @@ namespace jlog
     std::string toks2msg(std::vector<token> tokens, std::function<std::string(token)> formatter)
     {
         std::string msg;
-        for (token t: tokens)
+        for (const token& t: tokens)
         {
             msg += formatter(t);
         }