title: Svelte head title suffix
body: <p>I want to add a head title suffix like <code>- mywebsite</code> on each Svelte page.</p>
  
  <p>I'm struggling finding how to do it with ease and simplicity.</p>
  
  <p>On the svelte website source, we can see they do it manually: <a href="https://github.com/sveltejs/svelte/blob/1273f978084aaf4d7c697b2fb456314839c3c90d/site/src/routes/docs/index.svelte#L15" rel="noreferrer">https://github.com/sveltejs/svelte/blob/1273f978084aaf4d7c697b2fb456314839c3c90d/site/src/routes/docs/index.svelte#L15</a></p>
  
  <p>I started creating a component like this:</p>
  
  <pre><code>&lt;script&gt;
    export let title = false;
  &lt;/script&gt;
  
  &lt;svelte:head&gt;
    &lt;title&gt;
      {#if title}
        {title} • WebSite
      {:else}
        Website • Home suffix
      {/if}
    &lt;/title&gt;
  &lt;/svelte:head&gt;
  </code></pre>
  
  <p>But:</p>
  
  <ul>
  <li>I have a <code>&lt;title&gt; can only contain text and {tags}svelte(illegal-structure)</code> error</li>
  <li>I'm not sure it's the easiest way.</li>
  </ul>
  
  <p>How can an achieve what I want to do?</p>