mathlib3

5f1bfcf2 - chore(tactic/lean_core_docs): add API docs for core Lean tactics (#2371)

chore(tactic/lean_core_docs): add API docs for core Lean tactics (#2371) This is an attempt to get some documentation of most core Lean tactics into the API docs. See https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/undocumented.20core.20tactics (and the link in my second message in that thread) for background. Co-Authored-By: Rob Lewis <Rob.y.lewis@gmail.com> Co-Authored-By: Scott Morrison <scott@tqft.net> Co-Authored-By: Bryan Gin-ge Chen <bryangingechen@gmail.com>