Update include-markdown-custom.md
Update include-markdown-custom.md

```ruby
{%if include.selector%}<{{include.selector}} {%if include.classes%}class="{{include.classes}}"{%endif%} {%if include.id%}id="{{include.id}}{%endif%}">{%endif%}
  {% capture markdown %}{% include {{include.path}} %}{% endcapture %}{{ markdown | markdownify }}
{%if include.selector%}</{{include.selector}}>{%endif%}
```
daveaseeman/jekyll-include-markdown