Initial implementation of markdownlint-micromark package, micromark.mjs helpers, and tests.

test/snapshots/markdownlint-test-scenarios.js.md

@@ -10236,6 +10236,61 @@ Generated by [AVA](https://avajs.dev).
       `,
     }
 
+## every-markdown-syntax.md
+
+> Snapshot 1
+
+    {
+      errors: [],
+      fixed: `Every Markdown Syntax␊
+      =====================␊
+      ␊
+      ## Level 2 ATX Heading␊
+      ␊
+      ### Level 3 Closed ATX Heading ###␊
+      ␊
+      ---␊
+      ␊
+      Text *emphasized* **strong** ___emphasized+strong___.␊
+      Text \`code\` <strike>html</strike> <https://example.com/page>.␊
+      Text [link](https://example.com/page) [link][] [link] ![image][link].␊
+      ␊
+      Hard  ␊
+      line break␊
+      ␊
+      [link]: https://example.com/page "Title"␊
+      ␊
+      > Block quote␊
+      > > Nested␊
+      ␊
+      - Unordered␊
+      - List␊
+        - Items␊
+          Indented␊
+      ␊
+          Content␊
+      ␊
+      1. Ordered␊
+      2. List␊
+         1. Items␊
+            Indented␊
+      ␊
+            Content␊
+      ␊
+      \`\`\`markdown options␊
+      Fenced code block␊
+      \`\`\`␊
+      ␊
+          Indented code block␊
+      ␊
+      <p>␊
+      HTML block␊
+      </p>␊
+      ␊
+      <!-- markdownlint-disable-file -->␊
+      `,
+    }
+
 ## fenced-code-in-list.md
 
 > Snapshot 1