docs: add explorer example for advanced `sortFn` (#564)

Sidney

2023-12-28 e1b6a0014cabf07ddc7e7931912aece471959224

 quartz/plugins/transformers/index.ts

@@ -8,3 +8,4 @@
export { OxHugoFlavouredMarkdown } from "./oxhugofm"
export { SyntaxHighlighting } from "./syntax"
export { TableOfContents } from "./toc"
export { HardLineBreaks } from "./linebreaks"