* main:
  Document adding fixes in CONTRIBUTING.md (#24393)
  Sort formatter diagnostics in snapshots (#24375)
  [`pyupgrade`] Fix panic caused by handling of octals in `UP012` (#24390)
  Upgrade to nix v0.31.2 (#24385)
  Strip form feeds from indent passed to `dedent_to` (#24381)
  add recent move of the `deferred` submodule to `.git-blame-ignore-revs` (#24379)
  [ty] Fix extra_items TypedDict tests (#24367)
  [ty] Use `infer_type_expression` for validating PEP-613 type aliases (#24370)
  [`flake8-simplify`] Make the fix for `collapsible-if` (`SIM102`) safe in `preview` (#24371)
  [ty] Validate TypedDict fields when subclassing (#24338)
  [ty] pass type context to sequence literals in binary operations (#24197)
  Add release environment to notify-dependents job (#24372)
  Bump 0.15.9 (#24369)
  [ty] Move the `deferred` submodule inside `infer/builder` (#24368)
  [ty] Infer the `extra_items` keyword argument to class-based TypedDicts as an annotation expression (#24362)
  [ty] Validate type qualifiers in functional TypedDict fields and the `extra_items` keyword to functional TypedDicts (#24360)