ruff

b28dc9ac - Remove `--preview` as a required argument for `ruff server` (#12053)

Remove `--preview` as a required argument for `ruff server` (#12053) ## Summary `ruff server` has reached a point of stabilization, and `--preview` is no longer required as a flag. `--preview` is still supported as a flag, since future features may be need to gated behind it initially. ## Test Plan A simple way to test this is to run `ruff server` from the command line. No error about a missing `--preview` argument should be reported.