Fix the time format in `duration_to_string`

src/util/string.h

@@ -670,15 +670,15 @@ inline const std::string duration_to_string(int sec)
 
 	std::stringstream ss;
 	if (hour > 0) {
-		ss << hour << "h ";
+		ss << hour << " h";
 	}
 
 	if (min > 0) {
-		ss << min << "m ";
+		ss << min << " m";
 	}
 
 	if (sec > 0) {
-		ss << sec << "s ";
+		ss << sec << " s";
 	}
 
 	return ss.str();