Linking to optiongroups doesn't add *that* much, and is kind of a pain; meanwhile having the optiongroups adds an extra level of indentation.
Instead of options needing to be in an option group, they instead go in either the root node or nested in a usage node. Putting them in a usage node allows for more-or-less the previous behaviour but without making it the default.
Add `options` map for setting `ContentListing` options with key:val pairs; currently only used with `ContentListing::codeblock()` language arg.
Fix generated codeblock rst to print each line of code with indentation, and change it to use explicit an `code-block` so we can set a language on it.
Use `chformal` as example, comparing the `autocmd` output with `ChformalPass::formal_help()`, the json dump from the `ContentListing`, the command line output, and the RST generated (using `autocmd_rst`).
Includes bullet points on each step for more information.
Should eventually end up in `yosys_internals/extending_yosys/contributing.rst`, but it currently lives in `cmd/index_internal.rst` to avoid merge conflicts since cell help documentation is still WIP.
Also exports chformal source and help output to `docs/source/generated` during `make docs/prep`.
Keep techlibs folder hierarchy.
techlibs/* and passes/* groups are now nested under index_techlibs and index_passes respectively, with most (all?) of the passes/* pages getting proper headings, as well as backends/frontends/kernel. `index_passes_techmap` also references `index_techlibs`.
Split command reference toc in twain, one with maxdepth=2 and one with maxdepth=3, since passes and techlibs now have an extra level of nesting.
Move the `cmd_ref` link to the command reference, instead of top of the page.
Remove `index_internal` and `index_other` from the toc, and mark the pages as orphan. Internal commands get a note callout after the command reference toc (although this doesn't work for the pdf build), while other commands are linked in the warning for missing `source_location` (since that *should* be the only time when there are any commands in the "unknown" group).
Update autodoc extension versions, and mark the directives extension as not `parallel_read_safe` (it might be, but I'm not sure about how the xref lookups work if it is parallel so better to be safe).
Commands flagged as internal will display a warning, just like experimental commands.
Drop `passes/tests` group in favour of `internal` group, which is automatically assigned for any command without an assigned group which is flagged as internal.
