Update docs for users.populate_favorites

[bcantoni]

In the docs, users.populate_favorites is still shown as "not implemented" but the code support was made in #656.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. If this is still relevant, please comment to keep it open.

[jacalata]

Closing — the source docstring on users.populate_favorites is comprehensive (description, parameters, returns, working example — see tableauserverclient/server/endpoint/users_endpoint.py, Users.populate_favorites).

The stale "Not currently implemented" line lives only in the handwritten docs/api-ref.md on the gh-pages branch. PR #1832 replaces that page wholesale with a Sphinx autodoc build fed by the docstring, so it'll drop out on merge. No further code action needed here.