Duplicate sub headings lead to first link

[sethen]

If you have duplicate sub headings the link generated for them in the table of contents will just lead to the first match it finds. For instance, if you had:

# A Heading !heading
## A Subheading !heading

# Another Heading !heading
## A Subheading !heading

The table of contents generates the link based on the heading text. So both links for A Subheading would be the first subheading content.

[AaronDMarasco]

I think this is a limitation of Markdown itself.