Feature Request: Allow child anchor hash id references links when constructing markdown-menu

[alexdiliberto]

Basically, looking for a way to have the markdown-menu component optionally contain child references to a list of local anchor link within a file

So, given the following /app/guides/test.md

[services](#services) | [contact us](#contact_form)

... some text

### <a id="services"></a>Our Services

... some text

### <a id="contact_form"></a>Contact Form

This could build a markdown-menu with the following structure

Test
	Our Services
	Contact Form

Now on the /test route, the user can click "Our Services" and be taken to /test#services or click the "Contact Form" link and be taken to /test#contact_form

Currently looking into what would be required to make this possible