ci: add markdown linting workflow

Author: esadek

.github/workflows/lint.yaml

@@ -0,0 +1,9 @@
+name: Lint Markdown
+on: [push, pull_request]
+
+jobs:
+  rumdl:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: rvben/rumdl@v0

.gitignore

@@ -0,0 +1,2 @@
+# rumdl
+.rumdl_cache/

.rumdl.toml

@@ -0,0 +1,8 @@
+[global]
+respect-gitignore = true
+
+[MD013]
+line-length = 0
+
+[MD044]
+names = ["ADBC"]