title: Check line existence in laravel's trans()
body: <p>Lets say in my <code>lang/en/general.php</code> there are multiple translation lines for example:</p>
  
  <pre><code>"token" =&gt; "This password reset token is invalid.",
  
  "sent" =&gt; "Password reminder sent!",
  
  "reset" =&gt; "Password has been reset!",
  </code></pre>
  
  <p>But in my <code>lang/de/general.php</code> these lines are missing.</p>
  
  <p>So later, when I use the <code>Lang::get('general.token')</code> or simply <code>trans('general.token')</code></p>
  
  <p>The english version will return </p>
  
  <blockquote>
    <p>This password reset token is invalid.</p>
  </blockquote>
  
  <p>And the german (de) version will return</p>
  
  <blockquote>
    <p>general.token</p>
  </blockquote>
  
  <p>Is there any way I can handle a 'translation not found' function, like a filter but not creating a special class for it? For example, when a line has no translation, I want to throw an Exception.</p>
  
  <p>Thanks in advance!</p>