fix(jsx): mark <pre> body comments as handled to avoid duplication

[divybot]

Summary

<pre> element bodies are emitted verbatim via gen_from_raw_string_trim_line_ends instead of going through gen_jsx_with_opening_and_closing. This bypasses the normal child generation path that advances the comment tracker, so any comments inside the <pre> body remain unhandled.

When gen_node is then called for the closing </pre> tag, the unhandled comments are picked up by leading_comments_with_previous and emitted again as leading comments of the closing tag — duplicating them in the output. Because each pass adds another copy, the formatter never reaches a stable format and embedding hosts (e.g. deno fmt) panic with Formatting not stable. Bailed after 5 tries.

Reproduction

This is reported as denoland/deno#20403:

function ErrorPage500(props: ErrorPageProps) {
  return (
    <pre>
      {props.url}
      {/* {props.url} */}
    </pre>
  );
}

The first formatting pass produces:

function ErrorPage500(props: ErrorPageProps) {
  return (
    <pre>
      {props.url}
      {/* {props.url} */}
    /* {props.url} */
    </pre>
  );
}

Each subsequent pass adds another /* {props.url} */ line until the embedding formatter gives up.

Fix

In the <pre> branch of gen_jsx_element, after emitting the body as raw text, advance the comment tracker past the body range and mark every comment it visited as handled. The closing tag's leading-comment pass then finds nothing left to emit.

Test plan

• Added tests/specs/jsx/JsxElement/JsxElement_Pre_With_Comments.txt covering the original repro plus an adjacent-comments variant.
• Existing JSX/JsxEmptyExpression specs still pass.