False schema warning for <choices> inside <exercise> in valid multiple-choice PreTeXt markup

[geoff-cox]

These are common exercise interactives, so I am sure you are aware of these warnings by now (unless I am doing something wrong).

I am seeing a validation warning in VS Code from pretext-tools for markup that appears to be valid and builds correctly.

Warning

element "choices" not allowed here; 
expected the element end-tag or element "answer", "hint", 
or "solution"

• The project builds successfully.
• The output renders correctly.
• The warning appears only when the PreTeXt-tools extension is enabled in VS Code.
• If I disable PreTeXt-tools, the warning goes away.

Minimal Example

<exercise xml:id="ex-product-rule-mc">
  <title>Spot the derivative</title>

  <statement>
    <p>
      Which of the following is the derivative of 
      <m>h(x) = x^2 \sin(x)</m>?
    </p>
  </statement>

  <choices randomize="yes">
    <choice>
      <statement>
        <p>
          <m>h'(x) = 2x \cos(x)</m>
        </p>
      </statement>
      <feedback>
        <p>
          It is tempting to take the derivative directly 
          like this, but the correct approach is
          <md>(fg)' = f'g + fg'</md>.
        </p>
      </feedback>
    </choice>

    <choice correct="yes">
      <statement>
        <p>
          <m>h'(x) = 2x\sin(x) + x^2\cos(x)</m>
        </p>
      </statement>
      <feedback>
        <p>
          With <m>f = x^2</m> and <m>g = \sin(x)</m>, 
          the product rule gives
          <md>f'g + fg' = 2x\sin(x) + x^2\cos(x)</md>.
        </p>
      </feedback>
    </choice>

    <choice>
      <statement>
        <p>
          <m>h'(x) = 2x\sin(x) - x^2\cos(x)</m>
        </p>
      </statement>
      <feedback>
        <p>
          Close, but the product rule adds the two terms, 
          not subtracts them.
        </p>
      </feedback>
    </choice>

    <choice>
      <statement>
        <p>
          <m>h'(x) = x^2\cos(x)</m>
        </p>
      </statement>
      <feedback>
        <p>
          This differentiates only the <m>\sin(x)</m> factor, 
          leaving <m>x^2</m> alone. The product rule 
          requires differentiating each factor in turn: 
          <m>f'g + fg'</m>.
        </p>
      </feedback>
    </choice>
  </choices>
</exercise>