chore: Add use_field_init_shorthand = true to rustfmt

[orlp]

We already use this style, in fact failing to do so gives a clippy warning:

error: redundant field names in struct initialization
   --> crates/polars-stream/src/nodes/joins/equi_join.rs:380:13
    |
380 |             sampled_probe_morsels: sampled_probe_morsels,
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `sampled_probe_morsels`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_field_names
    = note: `-D clippy::redundant-field-names` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::redundant_field_names)]`

Might as well let rustfmt take care of this automatically for us.