title: RouteEnhancer with multiple widget links
body: <p>I have the following route enhancer configuration which is working so far:</p>
  
  <pre><code>routeEnhancers:
    Plugin:
      type: Extbase
      extension: Plugin
      plugin: Plugin
      routes:
        - { routePath: '/test/{var1}', _controller: 'ContactPerson::list', _arguments: { 'var1': '@widget_0/var1' } }
      defaultController: 'Plugin::list'
      defaults:
        var1: 'a'
      requirements:
        var1: '[a-z]'
  </code></pre>
  
  <p>The problem I am facing is that my widget has two arguments (get variables), the second one is optional. So I changed the route enhancer to this:</p>
  
  <pre><code>routeEnhancers:
    Plugin:
      type: Extbase
      extension: Plugin
      plugin: Plugin
      routes:
        - { routePath: '/test/{var1}/{var2}', _controller: 'ContactPerson::list', _arguments: { 'var1': '@widget_0/var1' , 'var2': '@widget_0/var2' } }
      defaultController: 'Plugin::list'
      defaults:
        var1: 'a'
        var2: ''
      requirements:
        var1: '[a-z]'
        var2: '[a-z]'
  </code></pre>
  
  <p>Unfortunately this does not work and my route is not recognized at all anymore.</p>