[Feature] Add in page anchor link support

[Vultik]

In Notion, you use the option "copy link to block" to create anchor link.
It will be great to have this support in Markdown when you have for example a table of content on top of the page.

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How implement in Markdown : https://gist.github.com/asabaylus/3071099

Btw, congratulations for the all new features you've added since my last issue report :)