feat(frontends/lean): add option 'elaborator.flycheck_goals'
feat(library/tools/tactic): add 'cases' alias for 'inversion' tactic
feat(library/tactic): refine 'get_unused_name'
fix(frontends/lean/elaborator): do not display flycheck related messages when --flycheck is not on
feat(library/tactic/inversion_tactic): basic 'inversion' tactic
fix(library/tactic/inversion_tactic): bug in injectivity transition
feat(library/tactic/inversion_tactic): add 'case ... with ...' variant that allows user to specify names for new hypotheses
fix(emacs): syntax highlight for 'cases ... with ...'
refactor(library/data/fin): simplify 'fin' module using new inversion tactic