Docs: highlight-next-line is not working

[natesilva]

Describe the bug Some code examples (such as the ones on https://electrodb.dev/en/modeling/schema/) have // highlight-next-line comments. I assume this is a directive to the documentation system that should have been processed and removed at build time.

In my browser (tested with Safari, Chrome, Firefox), these show up as comments and the lines are not highlighted.