feat: lints for redundant field names and needless struct updates

[ivov]

Adds two advisories that flag redundant struct-literal syntax.

  [info] Redundant field name
   ╭─[test.lis:7:11]
 6 │ fn make(x: int) -> Point {
 7 │   Point { x: x, y: 0 }
   ·           ──┬─
   ·             ╰── can be simpler
 8 │ }
   ╰────
  help: Replace `x: x` with `x` · code: [lint.redundant_field_names]

  [info] Needless struct update
   ╭─[test.lis:7:35]
 6 │ fn rebuild(base: Config) -> Config {
 7 │   Config { debug: true, port: 80, ..base }
   ·                                   ───┬──
   ·                                      ╰── has no effect
 8 │ }
   ╰────
  help: Remove `..base` · code: [lint.needless_update]