title: Why disabling mapping doesn't work in my vim editor?
body: <p>In my vim editor, I can find two mappings of  through following commands:</p>
  
  <pre><code>:imap &lt;CR&gt;
  </code></pre>
  
  <p>and it outputs:</p>
  
  <pre><code>i  &lt;CR&gt;        &amp;@&lt;SNR&gt;60_AutoPairsOldCRWrapper73&lt;SNR&gt;60_AutoPairsReturn
  i  &lt;CR&gt;          &lt;CR&gt;&lt;Plug&gt;DiscretionaryEnd
  </code></pre>
  
  <p>I want to disable the first one, so I add it into my .vimrc file:</p>
  
  <pre><code>iunmap &lt;buffer&gt; &lt;CR&gt;
  </code></pre>
  
  <p>but vim shows error <code>no such mapping</code> error when I open my editor, but actually I can disable the mapping by typing command in editor:</p>
  
  <pre><code>:iunmap &lt;buffer&gt; &lt;CR&gt;
  </code></pre>
  
  <p>I want to know why I cann't make it work in my .vimrc configuration file.</p>