mathlib

70b14cee - refactor(*): use is_scalar_tower instead of restrict_scalars (#4733)

refactor(*): use is_scalar_tower instead of restrict_scalars (#4733) - rename `semimodule.restrict_scalars` to `restrict_scalars` - rename `restrict_scalars` to `subspace.restrict_scalars` - use `is_scalar_tower` wherever possible - add warnings to docstrings about `restrict_scalars` to encourage `is_scalar_tower` instead