add linting to CI

Author: tjex

.github/workflows/lint.yml

@@ -0,0 +1,18 @@
+name: Lint
+
+on: [push, pull_request]
+
+jobs:
+  lint:
+    name: Luacheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - name: Setup
+        run: |
+          sudo apt-get update
+          sudo apt-get install luarocks -y
+          sudo luarocks install luacheck
+
+      - name: Lint
+        run: luacheck lua/ --globals vim