update my_ps1_scale for windows

bashrc

@@ -810,9 +810,10 @@ test -n "$SSH_CONNECTION" && __my_ps1_ssh_str="${__my_c5}SSH${__my_cdef} "
 
 __my_ps1_scale(){
     local last=$?
-    if null type stty && ! iswindows
+    if null type stty && ! ismsys
     then
         stty size | tr -d $'\n' | tr " " x
+        printf " "
     fi
     return $last
 }