Dvc.org: docs: should not need index files in every parent sidebar element

[jorgeorpinel]

From https://github.com/iterative/dvc.org/issues/727#issuecomment-545756811 with e.g. /doc/user-guide/contributing
Also related to #305

Using "source": false, on sidebar.json doesn't work unless it is the top level (e.g. get-started or understanding-dvc). In other levels, this breaks the engine.

Consider also automatically generating a list of H2s in child documents when no source field is used for a parent slug.

• And finish #727 after this.

[shcheklein]

index.js -> index.md? (or actually just index file, since it can have a custom name). Also, I would mention that source: false should be just working for 2+ level of the items in sidebar.

[jorgeorpinel]

source: false should only be working for 2+ level of the items in sidebar

Why not the top level as it works now, @shcheklein? Maybe I'm not getting this comment.

[shcheklein]

oh, it's my "russian" english when I'm typing too quick :) ... what I wanted to say is that source: false must work for all levels, including top level.