title: Auto-comment new line in Vim only for block comments
body: <p>When I start a new line at the end of a single-line comment in a <code>.{cpp,h}</code> file, <code>vim</code> is automatically commenting it. For example:</p>
  
  <pre><code>// This is a comment&lt;CR&gt;
  // | &lt;- Cursor is moved to `|`, `//` is automatically inserted. 
  </code></pre>
  
  <p>I'm not sure if this is a plugin or a setting. I can't see anything that looks like it'd do this in my <code>~/.vimrc</code>, and the loaded plugins are listed below. </p>
  
  <p>I <em>like</em> this for <code>/* */</code>-style <em>multiline</em> comments, but I don't want my <em>single-line</em> comments running over multiple lines by default. </p>
  
  <p>Which setting (or plugin) does this, and can I turn it off <em>for this comment type only</em>? </p>
  
  <p><code>:scriptnames</code> gives this:</p>
  
  <pre><code>
    1: /Users/simont/.vimrc
    2: /usr/local/share/vim/vim73/syntax/syntax.vim
    3: /usr/local/share/vim/vim73/syntax/synload.vim
    4: /usr/local/share/vim/vim73/syntax/syncolor.vim
    5: /usr/local/share/vim/vim73/filetype.vim
    6: /usr/local/share/vim/vim73/ftplugin.vim
    7: /usr/local/share/vim/vim73/syntax/nosyntax.vim
    8: /Users/simont/repositories/config-files/vim/colors/solarized.vim
    9: /usr/local/share/vim/vim73/plugin/getscriptPlugin.vim
   10: /usr/local/share/vim/vim73/plugin/gzip.vim
   11: /usr/local/share/vim/vim73/plugin/matchparen.vim
   12: /usr/local/share/vim/vim73/plugin/netrwPlugin.vim
   13: /usr/local/share/vim/vim73/plugin/rrhelper.vim
   14: /usr/local/share/vim/vim73/plugin/spellfile.vim
   15: /usr/local/share/vim/vim73/plugin/tarPlugin.vim
   16: /usr/local/share/vim/vim73/plugin/tohtml.vim
   17: /usr/local/share/vim/vim73/plugin/vimballPlugin.vim
   18: /usr/local/share/vim/vim73/plugin/zipPlugin.vim
   19: /usr/local/share/vim/vim73/scripts.vim
   20: /usr/local/share/vim/vim73/ftplugin/vim.vim
   21: /usr/local/share/vim/vim73/syntax/vim.vim
  </code></pre>