Problem: trailing spaces in code comments

Solution: fix them

src/config.hpp

@@ -80,8 +80,8 @@ namespace zmq
 
         //  On some OSes the signaler has to be emulated using a TCP
         //  connection. In such cases following port is used.
-        //  If 0, it lets the OS choose a free port without requiring use of a 
-        //  global mutex. The original implementation of a Windows signaler 
+        //  If 0, it lets the OS choose a free port without requiring use of a
+        //  global mutex. The original implementation of a Windows signaler
         //  socket used port 5905 instead of letting the OS choose a free port.
         //  https://github.com/zeromq/libzmq/issues/1542
         signaler_port = 0