[LTP] [PATCH 7/7] doc/Makefile: Add dependency on metadata/ltp.json

[Petr Vorel]

Hi Andrea, Cyril,

> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> NOTE: this should be applied after Andrea's work gets merged.
> https://patchwork.ozlabs.org/project/ltp/patch/20250206-doc_tests_list-v5-2-52110e1421a9@suse.com/

This actually fixes the regression (failure in CI introduced by 1bf344a3db
("doc: add tests catalog page").

I wrote it independently this week and forget to post. Therefore I put this what
turn out to be a fix at the end.

I would prefer to merge 5 commits (not having to rebase and have CI covering
actually the problem:

0c9b58e5b0 ("doc/Makefile: Add dependency on metadata/ltp.json")
9e46261aa6 ("configure: make: Add SPDX, update copyright")
cbbcb4a55f (".github: ci-sphinx-doc: Use make for building doc")
9624668a1f ("doc: documentation.rst: Update build instructions")
e59b9f8c8d ("doc/Makefile: Improve make targets")

E.g. not merging without any review besides configure and realtime changes.

Kind regards,
Petr