tsdb/wal: Move comment of w.writer.Append(...) to the WriteTo interface (#10198)
tsdb/wal: Move comment of w.writer.Append(...) to the WriteTo interface (#10198)

Signed-off-by: wanglipeng <251a253e4a7ff6b98a00ca06317e6371d491fce2@huayun.com>

Co-authored-by: wanglipeng <251a253e4a7ff6b98a00ca06317e6371d491fce2@huayun.com>
prometheus/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,prometheus/prometheus,prometheus/prometheus,prometheus/prometheus,keegancsmith/prometheus,prometheus/prometheus