mathlib

46566c5b - split(data/list/infix): Split off `data.list.basic` (#11062)

split(data/list/infix): Split off `data.list.basic` (#11062) This moves `list.prefix`, `list.subfix`, `list.infix`, `list.inits`, `list.tails` and `insert` lemmas from `data.list.basic` to a new file `data.list.infix`.