mathlib

9afc6f2f - docs(tactics): tautology (#1860)

docs(tactics): tautology (#1860) * added a short description of the tautology tactic * added a short description of the tautology tactic * Update docs/tactics.md Co-Authored-By: Johan Commelin <johan@commelin.net> Co-authored-by: Johan Commelin <johan@commelin.net> Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>