build: bump core from 462fcd7 to 6b84118 in the submodules group

Bumps the submodules group with 1 update: [core](https://github.com/tree-sitter/tree-sitter).


Updates `core` from `462fcd7` to `6b84118`
- [Release notes](https://github.com/tree-sitter/tree-sitter/releases)
- [Commits](tree-sitter/tree-sitter@462fcd7...6b84118)

---
updated-dependencies:
- dependency-name: core
  dependency-version: 6b84118e3304a6627b98af21ab7a23af8fcd453e
  dependency-type: direct:production
  dependency-group: submodules
...

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Author: dependabot[bot]