Function fetch_latest_stable_version 

pub fn fetch_latest_stable_version(
    client: &Client,
    cli_label: &str,
) -> Result<String>

Fetch the latest stable kernel version from kernel.org.

Selects from the releases array (moniker “stable” or “longterm”), requiring patch version >= 8 to avoid brand-new major versions that may have build issues on CI runners.

When client is the process-wide shared_client singleton, routes through RELEASES_CACHE; other clients bypass the cache via pointer-equality and exercise fetch_releases directly — see cached_releases_with for details.

cli_label prefixes diagnostic status output (e.g. "ktstr" or "cargo ktstr").