toc: toc_depth as range

[klml]

Currently toc_depth defines up to which section level “n” ( <h1> to , where 1 <= n <= 6) to include in the Table of Contents.

Would be nice to have it not only defining up to which but from and up to which section level to include in the Table of Contents.
So you could include section level only from range h2 to h6 to the Table of Contents.

I could pass in a PR, should I change toc_depth to an array or introduce a new config value (e.g. toc_height)?

use case

I want to use h1 as sole document title and so it should not be part of the ToC.

[waylan]

This may be a duplicate of #637. However that discussion took a lot of turns so it is unclear. Regardless, the final comment on that issue is relevant:

I use the meta extension and include the title of the document in the meta-data. My templates then insert that Title into the HTML separate from the body of my document which comes from the Markdown. Therefore, I never get the document title included in my TOC.

I work on Python-Markdown as a volunteer in my spare time and I don't have any reason to use up my spare time on features I have no use for. Therefore, if this is something you care about, you need to do the work. If someone submits a PR, I'll take the time to review it, and if it passes my review, I'll merge it. Other than that, I have more important things (to me) to work on.