docs: minor errors

[romain-dartigues]

I did fix a few errors in the documentation I came through today.

Quick questions:

1. There are a lot of Markdown pages (connectors, support…); would you accept if I converted them in ReST to get the benefits of the Sphinx domains (ie: ref, samp…)?
2. There are a lot of "generated ReST files", (apidocs/, connectors/, facts/, operations/, etc.); why not use autodoc and remove a lot of complexity (and avoid errors such as pyinfra/docs/operations/opkg.rst:22: WARNING: Lexing literal_block 'opkg.packages(\n packages: str | typing.List[str]="", present: <class \'bool\'>=True,\n latest: <class \'bool\'>=False, update: <class \' bool\'>=True, **kwargs,\n)' as "python" resulted in an error at token: "'". Retrying in relaxed mode. [misc.highlighting_failure])

[Fizzadar]

Thanks for fixing this up, @romain-dartigues!

Quick questions:

1. There are a lot of Markdown pages (connectors, support…); would you accept if I converted them in ReST to get the benefits of the Sphinx domains (ie: ref, samp…)?

Let's hold off on this for now, I'm weighing up moving away from sphinx to mkdocs/similar for simplicity so markdown is probably the future.

2. There are a lot of "generated ReST files", (apidocs/, connectors/, facts/, operations/, etc.); why not use [autodoc](https://www.sphinx-doc.org/en/master/usage/extensions/autodoc.html) and remove a lot of complexity (and avoid errors such as `pyinfra/docs/operations/opkg.rst:22: WARNING: Lexing literal_block 'opkg.packages(\n    packages: str | typing.List[str]="", present: <class \'bool\'>=True,\n    latest: <class \'bool\'>=False, update: <class \' bool\'>=True, **kwargs,\n)' as "python" resulted in an error at token: "'". Retrying in relaxed mode. [misc.highlighting_failure]`)

Autodocs output wasn't right for the pyinfra documentation (this is many years ago though, so I've long forgotten why :)), I know it can be tweaked but it'd be a similar effort to the current custom setup which works fine. I think unless there's a particular benefit to doing so the current system does the job well enough.