fix(tests/lean/run/tactic14): remove not_intro, it is not needed anymore

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(frontends/lean/elaborator): distribute application over choice, this feature improves the support for overloaded aliases

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(frontends/lean/elaborator): distribute application over choice, this feature improves the support for overloaded aliases