Fix #256: Fix direction of f_op lemmas
Turn all f_op lemmas to have shape f (x ⋅ y) = f x ⋅ f y, following the plan
in !295 (comment 39151).
Supersedes !295 (closed).
Turn all f_op lemmas to have shape f (x ⋅ y) = f x ⋅ f y, following the plan
in !295 (comment 39151).
Supersedes !295 (closed).