Update grammar for Tree-sitter ABI 14 compatibility

[BernardIgiri]

This updates the grammar to work with [Tree-sitter ABI 14](https://tree-sitter.github.io/tree-sitter/using-parsers#abi-compatibility), which is required by Helix Editor 25 and other modern tooling.

I was trying to use this grammar in Helix, but encountered this error:

QueryError { message: "Incompatible language version 8. Expected minimum 13, maximum 14", kind: Language }

To fix it, I re-initialized the grammar with tree-sitter init, then regenerated the parser with:

tree-sitter generate --abi=14

I also verified syntax highlighting by adding a grammar entry to Helix:

# languages.toml
[[grammar]]
name = "fluent"
source = { git = "https://github.com/BernardIgiri/tree-sitter-fluent.git", rev = "master" }

[[language]]
name = "fluent"
scope = "source.fluent"
file-types = ["ftl"]
comment-token = "#"

And using the following highlights.scm query file:

; Comments
(block_comment) @comment
(comment) @comment
(resource_comment) @comment

; Messages and terms
(message) @function
(term) @constant

; Identifiers
(identifier) @variable
(term_identifier) @constant

; Patterns (string content)
(pattern) @string

With this, Fluent .ftl files now display correctly in Helix 25.

Let me know if any changes are required. Thank you!

[alerque]

Are all the changes in this PR generated by that one command? Even the .editorconfig addition and stuff like that?

[BernardIgiri]

Are all the changes in this PR generated by that one command? Even the .editorconfig addition and stuff like that?

Yes, tree-sitter init alone adds these files:

.editorconfig
.gitattributes
CMakeLists.txt
Cargo.toml
Makefile
Package.swift
bindings/
go.mod
pyproject.toml
setup.py
tree-sitter.json

Then tree-sitter generate --abi=14 modifies:

src/grammar.json
src/parser.c
src/tree_sitter/parser.h

And adds:

src/node-types.json
src/tree_sitter/alloc.h
src/tree_sitter/array.h

I'm thinking that .editorconfig and .gitattributes aren't really necessary though.

[alerque]

Strictly necessary or not I'll review them differently knowing they are auto-generated from project-adjacent tooling than I would if they were concocted by one party according to their preferences and combined with something else auto-generated.

That being said it probably makes sense to split this into at least 2 commits to see what is happening where, and to make future updates to either of these actions more direly comparable to ease future reviews as well.

[BernardIgiri]

Strictly necessary or not I'll review them differently knowing they are auto-generated from project-adjacent tooling than I would if they were concocted by one party according to their preferences and combined with something else auto-generated.

That being said it probably makes sense to split this into at least 2 commits to see what is happening where, and to make future updates to either of these actions more direly comparable to ease future reviews as well.

I'm moving this PR to #2 so I can continue using this repo for my personal use of Helix Editor. That PR separates the changes into 2 commits as requested.