Allow for id attribute in a tags in markdown

[maudetes]

This would allow for adding anchors in markdown contents.
Exemple :

# Cookie <a id="cookie"></a>

We want a section full of cookies (the edible ones).

We could then use the anchor as /posts/my-post-about-food/#cookie

Notes

I haven't found any other simpler way to add anchors with our markdown parser.
I haven't checked yet for security warning on adding these.

[maudetes]

Well, it is a complicated topic with security issues : markdown-it/markdown-it#28.
Using name would be safer but not cleared of all risks?
The need for anchors may not be worth the trouble.