fix(tactic/ring): more precise pattern match for div (#1557)
* fix(tactic/ring): more precise pattern match for div
* add test
* fix instance check for div
* chore(algebra/quadratic_discriminant): add braces in have steps
* use norm_num instead of ring to evaluate exponents
* fix norm_num uses
* fix norm_num pow bug
* bugfix
* fix proof
Co-authored-by: Rob Lewis <Rob.y.lewis@gmail.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
