Element name 'mode' is invalid for XSLT 3 stylesheet.

I'm not 100% sure where this error is even coming from, but I have this plugin installed for XML support, so this is the most likely culprit.

I'm using the latest VS Code on Windows 10. I load an XSLT stylesheet that starts like this:

<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <xsl:output method="text"/>
  <xsl:mode on-no-match="fail"/>

In my editor xml:mode is underlined; the error says:

Element name 'mode' is invalid.

One of the following is expected:
 - declaration
 - variable
 - param
 - WC[##other:"http://www.w3.org/1999/XSL/Transform"]

Error indicated by:
 {http://www.w3.org/1999/XSL/Transform}
with code: xml(cvc-complex-type.2.4.a)

I'm pretty sure this is valid XSLT 3. Perhaps the plugin is using an outdated schema definition for XSLT 2.x? How can we get this updated? I would file a pull request, but I don't have the faintest idea where this would be defined.

No file or test is named in the report. Start by loading the supplied XSLT example and tracing the plugin's schema-validation entry point; done means the XSLT 3 xsl:mode declaration with on-no-match is accepted without the invalid-element diagnostic.