[TxMt] XHTML tags flagged as errors

I use an XHTML template language for my web applications that allows me to define my own tags such as <s:embed>...</s:embed>. I set the language for these files to HTML so that embedded stylesheets, scripts, etc. are formatted correctly.

With HTML bundle update yesterday, these custom tags are now highlighted as errors with the scope invalid.illegal.unrecognized-tag.html

This has worked great for me for at least the last eight years at least. This new behavior is rather annoying.

Is there a way that I can avoid the HTML bundle flagging these custom tags as errors?