fix swh-graph sphinx table of content
the table of content of swh-graph doc doesn't look good, it only shows a few of the existing subpackages (and in a weird order)
Migrated from T2056 (view on Phabricator)
the table of content of swh-graph doc doesn't look good, it only shows a few of the existing subpackages (and in a weird order)
Migrated from T2056 (view on Phabricator)