message: Restore `view-markdown-source` buttons
diff: @@ -40,7 +40,7 @@ async function showSource(): Promise<void> {
  sourceButton.disabled = true;
  const source = buttonBodyMap.get(sourceButton) ?? fetchSource();
  - const rendered = await buttonBodyMap.get(renderedButton) ?? select('.blob.instapaper_body')!;
  + const rendered = await buttonBodyMap.get(renderedButton) ?? select('.blob.js-code-block-container')!;
  buttonBodyMap.set(sourceButton, source);
  buttonBodyMap.set(renderedButton, rendered);
  @@ -74,7 +74,7 @@ async function showRendered(): Promise<void> {
  }
  async function init(): Promise<false | void> {
  - if (!select.exists('.blob.instapaper_body')) {
  + if (!select.exists('.blob .markdown-body')) {
  return false;
  }
  