Fix 'to to' in snapbackDuration

Editor assessment

The subject pinpoints the typo exactly: the doubled 'to to' in the snapbackDuration documentation of refresher. That is a complete description of a one-token fix, quoted so the defect is visible without opening anything. docs(refresher) is the correct pairing. No body or footer, and none is required; the pull number gives provenance. Wording is compact and clean. Everything a typo-fix message needs is present in its header alone.