Rollup merge of #65834 - Mark-Simulacrum:driver-clean, r=nikomatsakis

Remove lint callback from driver

This is leftover from a restructuring of lint registration for drivers; it should now happen via the register_lints field on Config rather than this function.

This is not used by anyone to my knowledge (including the compiler itself); it was introduced in an abandoned refactor in #65193.

src/librustc_driver/lib.rs

@@ -106,8 +106,6 @@ pub fn abort_on_err<T>(result: Result<T, ErrorReported>, sess: &Session) -> T {
 pub trait Callbacks {
  /// Called before creating the compiler instance
  fn config(&mut self, _config: &mut interface::Config) {}
- /// Called early during compilation to allow other drivers to easily register lints.
- fn extra_lints(&mut self, _ls: &mut lint::LintStore) {}
  /// Called after parsing. Return value instructs the compiler whether to
  /// continue the compilation afterwards (defaults to `Compilation::Continue`)
  fn after_parsing(&mut self, _compiler: &interface::Compiler) -> Compilation {