Add support for the `auto_identifiers`, `gfm_auto_identifiers`, and
`ascii_identifiers` extensions in the man reader. Section headings
parsed from .SH and .SS macros now receive auto-generated id
attributes when the extension is enabled, enabling `--toc` to
produce working anchor links.
- Add `autoIdExtensions` to default man extensions [behavior change]
- Add `HasReaderOptions`, `HasLogMessages` and `HasIdentifierList` to
`ManState` to run `registerHeader`
Closes#8852.
Meher Chaitanya