title: How to set shotcuts to toggle comments in vimrc file
body: <p>I want to create a shortcut <kbd>ctrl</kbd>+<kbd>c</kbd> to toggle comment for .vhd files, so thing should be like this:</p>
  
  <p>when I press <kbd>Ctrl</kbd>+<kbd>c</kbd>, in vim normal mode, it should add "-- " at the begining of the actual line.</p>
  
  <p>I tried to add "nmap &lt; C-c > &lt;--space> " in my vimrc file,but it didn't work.</p>