title: no-duplicate-selectors error for different selectors inside the same file
body: <p>I am using stylelint within a CSS-IN-JS project (here using astroturf, but I face the same pattern using any CSS-IN-JS library such as styled-components as well).</p>
  
  <p>I define different styled elements within the same file, and therefore sometimes end up having duplicated selectors and/or import rules.</p>
  
  <pre><code>/* style.js */
  import styled from 'astroturf';
  
  export const StyledComponentA = styled('div')`
    transform: scale(0);
  
    &amp;.visible {
      transform: scale(1);
    }
  `;
  
  export const StyledComponentB = styled('div')`
    opacity: 0;
  
    /* -&gt; stylelint error: Unexpected duplicate selector "&amp;.visible" */
    &amp;.visible {
      opacity: 1;
    }
  `;
  </code></pre>
  
  <p>Which I compose this way:</p>
  
  <pre><code>import React from 'react';
  import { StyledComponentA, StyledComponentB } from './style';
  
  export const Component = ({ isVisible }) =&gt; (
    &lt;StyledComponentA visible={isVisible}&gt;
      &lt;StyledComponentB visible={isVisible}&gt;Whatever&lt;/StyledComponentB&gt;
    &lt;/StyledComponentA&gt;
  );
  </code></pre>
  
  <p>Is there a way to set these stylelint rules on blocks instead of an entire file?</p>