Match MDX code highlight metadata parsing

Author: aurorascharff

eslint-local-rules/__tests__/fixtures/src/content/valid-highlight.md

@@ -1,3 +1,7 @@
 ```js [[1, 1, "submitAction"]]
 function submitAction() {}
 ```
+
+```js [[1, 1, "\\"hidden\\""]]
+const mode = "hidden";
+```

eslint-local-rules/rules/lint-markdown-code-blocks.js

@@ -45,7 +45,7 @@ module.exports = {
         // For each supported code block, run the compiler and reconcile metadata.
         for (const block of blocks) {
           for (const message of validateInlineHighlights(
-            block.fence.metaText,
+            block.meta,
             block.code
           )) {
             context.report({

eslint-local-rules/rules/markdown.js

@@ -16,6 +16,7 @@ const {parseFenceMetadata} = require('./metadata');
  * @property {{lineIndex: number, rawText: string, metaText: string, range: [number, number]}} fence
  * @property {string} filePath
  * @property {string} lang
+ * @property {string} meta
  * @property {import('./metadata').FenceMetadata} metadata
  */
 
@@ -76,6 +77,7 @@ function parseMarkdownFile(content, filePath) {
 
       blocks.push({
         lang: rawLang || normalizedLang,
+        meta: node.meta || metaText.trim(),
         metadata,
         filePath,
         code: node.value || '',