added support for code-blocks

converts

```
`function oexchange_target_link($array) {
  $array["links"][] = array("rel" => "http://oexchange.org/spec/0.8/rel/resident-target",
    "href" => "http://example.com",
    "type" => "application/xrd+xml");
  return $array;
}
add_filter('webfinger', 'oexchange_target_link');`
```

into

```
```
function oexchange_target_link($array) {
  $array["links"][] = array("rel" => "http://oexchange.org/spec/0.8/rel/resident-target",
    "href" => "http://example.com",
    "type" => "application/xrd+xml");
  return $array;
}
add_filter('webfinger', 'oexchange_target_link');
```
```