title: Path helper for a wildcard route in Phoenix (Elixir)
body: <p>I'd like to use a path helper for a wildcard route, defined like this:</p>
  
  <pre><code>get("/thing/*sub_path", ThingController, :index)
  </code></pre>
  
  <p>There is indeed a path helper, but it does is of course not what I need :</p>
  
  <pre><code>iex(3)&gt; MyAppWeb.Router.Helpers.thing_path(MyAppWeb.Endpoint, :index, sub_path: "test/thing")
  "/thing?sub_path=test%2Fthing"
  </code></pre>
  
  <p>What I need would be, instead:</p>
  
  <pre><code>"/thing/test/thing"
  </code></pre>
  
  <p>Any clue on how to achieve this ?</p>