Update grammar to cover array spreads, variant type spreads and newer operators.

[mvaled]

Disclosure: This PR was generated with AI assistance and reviewed by the author. The author's goal is to improve the Emacs rescript-ts-mode (jjlee/rescript-mode#19).

Summary

This PR updates the Tree-sitter grammar to better match recent ReScript language features across three areas:

1. ReScript 12 operator support
2. Variant spread syntax
3. Array spread expressions

What changed

1. ReScript 12 operator support

Added grammar support for the newer operator syntax introduced in ReScript 12, including:

• modulo: %

• bitwise operators:

  • &&&
  • |||
  • ^^^
  • ~~~

• shift operators:

  • <<
  • >>
  • >>>

2. Variant spread syntax

Added support for:

• variant type spreads, e.g.

  type base = Start | Stop | Pause
  type extended = | ...base | Resume

• variant pattern spreads, e.g.

  let handle = (event: extended) =>
      switch event {
      | ...base as core => Console.log2("base", core)
      | Resume => Console.log("resuming")
      }

3. Array spread expressions

Added support for spread elements inside array literals, including multiple spreads, e.g.

let animals = ["🐶", "🐱", "🐷"]
let moreAnimals = [...animals, "🐔", "🐴", "🐮", ...otherAnimals]

This brings the grammar in line with array spread syntax available since ReScript v11.