Doc entries disappearing in the luma.gl site

[tsherif]

The site is staged here: https://tsherif.github.io/luma.gl/docs

Some entries in the table of contents aren't showing up in the generated sidebar, e.g. the first entry in the API reference section is a submenu "Overview" with README titled "Overview":

But it doesn't show up in the sidebar:

It is however accessible via direct navigation: https://tsherif.github.io/luma.gl/docs/api-reference

A few other entries that aren't listed:

• https://tsherif.github.io/luma.gl/docs/get-started
• https://tsherif.github.io/luma.gl/docs/contributor-guide

It seems to be only files named README.md, but changing the names didn't help.

[ibgreen]

There are some particularities in ocular's processing of markdown.

• README.md files are treated as the default entry for that directory. If you delete the /README part it should work.
• There must be a # <title> markdown stanza on the first line of the file

I did this in the PR I just opened on luma.gl website and it seems to have fixed it.

While easy to fix, there should be better defaults and reasonable warnings for these cases.