Slice with a stride and no upper bound (arr[1: :4]) is displayed as arr[1::4], which doesn't parse #2807

Subscript::Slice with upper_bound: None and a stride prints the two colons next to each other, and the tokenizer then reads :: (cast):

SELECT ([1, 2, 3, 4, 5, 6, 7, 8, 9])[1: :4]
  -> displays as: SELECT ([1, 2, 3, 4, 5, 6, 7, 8, 9])[1::4]
  -> reparse: Expected: a data type name, found: 4 at Line: 1, Column: 41
SELECT ([1, 2, 3, 4, 5, 6, 7, 8, 9])[: :4]
  -> displays as: SELECT ([1, 2, 3, 4, 5, 6, 7, 8, 9])[::4]
  -> reparse: Expected: an expression, found: :: at Line: 1, Column: 38
SELECT ([1, 2, 3, 4, 5, 6, 7, 8, 9])[1:-:4]
  -> round-trips (fine)

DuckDB documents [1:-:4] for this (https://duckdb.org/docs/stable/sql/functions/list#slicing), but it also runs [1: :4] (returns [1, 5, 9]), and the parser accepts it. Something like [1: :4] in Display would round-trip.

Tested with DuckDbDialect on main ce12f1f (also 0.63.0 and 0.58.0).

Found with a property-based fuzzer (round trip check); I used AI assistance for triage and verified every case above.