title: "set iskeyword-=_" not being set from vimrc
body: <p>Basically the title. When I include in my vimrc</p>
  
  <pre><code>set iskeyword-=_
  </code></pre>
  
  <p>and save it, when I reload gvim and type</p>
  
  <pre><code>:set iskeyword
  </code></pre>
  
  <p>I still see</p>
  
  <pre><code>iskeyword=@,48-57,_,192-255
  </code></pre>
  
  <p>As you can see, the '_' is still there. If I just <code>:set iskeyword-=_</code> it works as intended. Why doesn't this work from my vimrc? Is there an alternate way I can get around this and if so how?</p>