feat(tests)!: new infrastructure based on makefile

Problem: Not easy to run all checks and tests locally. Redundant CI
workflows.

Solution: Separate CI into two workflows:
 * lint: Lua files (stylua, luals), query files (valid captures,
   predicates, directives using tsqueryls), docs
   (SUPPORTED_LANGUAGES.md) -- does not need parser installation
 * tests: parsers (ABI compatibility), query files (tsqueryls on
   Linux/macOS; nvim on Windows), highlight and indent tests (separated
   for better readability) -- needs parser installation (but only once)

Switch to https://github.com/nvim-treesitter/highlight-assertions fork
with ABI 15 support.

Run all tests (on Linux and macOS) through `make` (`formatlua`,
`checklua`, `lintquery`, `formatquery`, `checkquery`, `docs`, `tests`),
which downloads and caches all necessary dependencies.

Remove `update-readme` workflow (replaced by lint job on PRs).

.github/workflows/lint.yml

@@ -1,52 +1,50 @@
 name: Lint
 
 on:
+  push:
+    branches:
+      - "main"
   pull_request:
     branches:
       - "main"
+  workflow_dispatch:
 
 jobs:
-  luacheck:
-    name: Luacheck
+  lua:
+    name: Lint Lua files
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
 
-      - name: Prepare
+      - name: Format
         run: |
-          sudo apt-get update
-          sudo apt-get install luarocks -y
-          sudo luarocks install luacheck
-
-      - name: Run Luacheck
-        run: luacheck .
-
-  stylua:
-    name: StyLua
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - name: Lint with stylua
-        uses: JohnnyMorganz/stylua-action@v4
-        with:
-          token: ${{ secrets.GITHUB_TOKEN }}
-          version: latest
-          args: --check .
-
-  format-queries:
-    name: Format queries
-    runs-on: ubuntu-latest
-    env:
-      NVIM_TAG: nightly
-    steps:
-      - uses: actions/checkout@v4
-      - uses: tree-sitter/setup-action/cli@v1
-      - name: Prepare
-        run: |
-          bash ./scripts/ci-install.sh
+          make formatlua
+          git diff --exit-code
 
       - name: Lint
+        run: make checklua
+
+  queries:
+    name: Lint query files
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Format
         run: |
-          nvim -l scripts/install-parsers.lua query
-          nvim -l scripts/format-queries.lua
+          make formatquery
+          git diff --exit-code
+
+      - name: Lint
+        run: make lintquery
+
+  readme:
+    name: Lint docs
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Check SUPPORTED_LANGUAGES
+        run: |
+          make docs
           git diff --exit-code