grind
This PR implements E-matching for the (WIP) `grind` tactic. We still need to finalize and internalize the new instances.
This PR internalize nested ground patterns when activating ematch theorems in the (WIP) `grind` tactic.
This PR adds support for activating relevant theorems for the (WIP) `grind` tactic. We say a theorem is relevant to a `grind` goal if the symbols occurring in its patterns also occur in the goal.