Add Haxe language support via vshaxe/haxe-language-server

Includes full setup with ls provider, tests, docs, etc.

.github/workflows/pytest.yml

@@ -386,6 +386,10 @@ jobs:
       - name: Install ansible-core and ansible-lint (for Ansible language server tests)
         shell: bash
         run: uv run pip install ansible-core ansible-lint
+      - name: Install Haxe
+        uses: krdlab/setup-haxe@v2
+        with:
+          haxe-version: 4.3.7
       - name: Install Elm
         shell: bash
         run: npm install -g elm@0.19.1-6