style: Enforce linting rules on markdown files

* chore: add markdownlint-cli2 and config for mkdocs

* style: enforce linting rules on mkdocs md files

* chore: tweaks to markdownlint rules

* style: linting changelog

* style: linting release notes

* style: linting .github md files

* style: further linting of docs

* style: linting readmes

* chore: update linting script entries

* docs: tweak release after rebase

* chore: simplify root md linting config

* chore: extend base config

* chore: implement requested changes

* chore: remove unnecessary exception

* chore: fix comment type

* styling: single config + list spacing

* chore: implement requested changes

* chore: use .cjs files for markdownlint config

* chore: implement requested changes

.github/.markdownlint-cli2.cjs

@@ -0,0 +1,14 @@
+
+const options = require('../.markdownlint-cli2.cjs');
+"use strict";
+
+module.exports = {
+  globs: [ "**/*.md" ],
+  config: {
+    // Re-use the base config
+    ...options.config,
+
+    // Allow first line to not be top level heading
+    MD041: false
+  }
+};