Fix double cleaning of HTML tags

In markdown, in HTML code (or XML, SVG, etc), a sanitation mechanism that Prism
needs was in place to drop what looks like HTML tags.
We don’t need that here in refractor, because we don’t have strings of HTML.
That is, we also don’t need to sanitize again, because with that in place we
dropped *safe* tags.

Closes GH-64.

lang/markdown.js

@@ -390,11 +390,7 @@ export default function markdown(Prism) {
           })
         }
       } else {
-        env.content = Prism.highlight(
-          textContent(env.content.value),
-          grammar,
-          codeLang
-        )
+        env.content = Prism.highlight(env.content.value, grammar, codeLang)
       }
     })
     var tagPattern = RegExp(Prism.languages.markup.tag.pattern.source, 'gi')

script/languages.js

@@ -2,6 +2,7 @@
  * @typedef {import('babel__core').PluginObj} PluginObj
  */
 
+import assert from 'node:assert/strict'
 import fs from 'node:fs/promises'
 import chalk from 'chalk'
 import babel from '@babel/core'
@@ -47,11 +48,18 @@ async function generate(name) {
     typeof info.alias === 'string' ? [info.alias] : info.alias || []
   ).sort(alphaSort())
 
-  /** @type {string} */
-  // @ts-expect-error: TS is wrong.
-  const doc = babel.transformSync(String(buf), {
+  const result = babel.transformSync(String(buf), {
     plugins: [fixWrapHook]
-  }).code
+  })
+  assert(result, 'expected `result`')
+  let doc = result.code
+  assert(doc, 'expected `doc`')
+
+  if (id === 'markdown') {
+    // A useless function only used in `markdown` for us: our `value` is
+    // already text content.
+    doc = doc.replace(/textContent\(env\.content\.value\)/, 'env.content.value')
+  }
 
   await fs.writeFile(
     new URL('../lang/' + name + '.js', import.meta.url),
@@ -105,6 +113,7 @@ function fixWrapHook() {
       },
       // If a syntax is assigning `Prism.highlight` to `env.content`, we should
       // add the result to `env.content` instead of `env.content.value`.
+      // This is currently only done for markdown.
       AssignmentExpression: {
         enter(path) {
           const callee = path.get('right.callee')
@@ -113,7 +122,7 @@ function fixWrapHook() {
             callee.matchesPattern('Prism.highlight') &&
             path.get('left').matchesPattern('env.content')
           ) {
-            // @ts-expect-error Mutate.
+            // @ts-expect-error Patch custom field, handled next.
             path.get('left').node.ignoreValueSuffix = true
           }
         }
@@ -124,7 +133,7 @@ function fixWrapHook() {
         enter(path) {
           if (
             this.inWrapHook &&
-            // @ts-expect-error Mutate.
+            // @ts-expect-error Patched custom field.
             !path.node.ignoreValueSuffix &&
             path.matchesPattern('env.content')
           ) {

test/fixtures/markdown-code/input.txt

@@ -0,0 +1,7 @@
+```html
+<h1>a</h1>
+```
+
+```css
+* { color: red; }
+```

test/fixtures/markdown-code/output.html

@@ -0,0 +1,7 @@
+<span class="token code"><span class="token punctuation">```</span><span class="token code-language">html</span>
+<span class="token code-block language-html"><span class="token tag"><span class="token tag"><span class="token punctuation">&#x3C;</span>h1</span><span class="token punctuation">></span></span>a<span class="token tag"><span class="token tag"><span class="token punctuation">&#x3C;/</span>h1</span><span class="token punctuation">></span></span></span>
+<span class="token punctuation">```</span></span>
+
+<span class="token code"><span class="token punctuation">```</span><span class="token code-language">css</span>
+<span class="token code-block language-css"><span class="token selector">*</span> <span class="token punctuation">{</span> <span class="token property">color</span><span class="token punctuation">:</span> <span class="token color">red</span><span class="token punctuation">;</span> <span class="token punctuation">}</span></span>
+<span class="token punctuation">```</span></span>