clang/Driver/Options.td, docs/UsersManual.rst and docs/ClangCommandLineReference.rst

As I know the documentation of command line options are in two places:

* include/clang/Driver/Options.td (DocBreif and HelpText are used to
generate docs/ClangCommandLineReference.rst
(Clang command line argument reference — Clang 15.0.0git documentation ))
* docs/UsersManual.rst : This is manually edited. It is more like a
book. My understanding is that the manual only contains frequently
used options.

docs/ClangCommandLineReference.rst actually lacks lots of stuff from
docs/UsersManual.rst (I have seen people complaining that more than a
half of options on ClangCommandLineReference have no documentation). I
wonder whether there is a better way organizing the documentation. For
example, if some description are written in docs/UsersManual.rst, it'd
be nice for ClangCommandLineReference to inherit those.

(The documentation of attributes is in a separate file:
include/clang/Basic/AttrDocs.td
(Attributes in Clang — Clang 15.0.0git documentation) Does Options.td
need to learn from it?)