use proper way of commenting

Author: wolfv

vinca/templates/bld_ament_cmake.bat.in

@@ -12,9 +12,9 @@ rd /s /q build
 mkdir build
 pushd build
 
-@rem set "CMAKE_GENERATOR=Ninja"
+:: set "CMAKE_GENERATOR=Ninja"
 
-@rem try to fix long paths issues by using default generator
+:: try to fix long paths issues by using default generator
 set "CMAKE_GENERATOR=Visual Studio %VS_MAJOR% %VS_YEAR%"
 
 if "%PKG_NAME%" == "ros-@(ros_distro)-mimick-vendor" (