[Feature] Support tree shaking for mdx files

[Codpoe]

I use mdx files as routing files in FileSystemRouter, such as src/pages/a.mdx?pick=default&pick=frontmatter, and then use @mdxjs/rollup to compile these mdx files and convert them to JS format.

However, currently the tree-shake vite plugin of vinxi does not support the mdx and md ext, so I would like to ask if it can be implemented.

vinxi/packages/vinxi/lib/plugins/tree-shake.js

Line 93 in 93d236a

if (query.has("pick") && ["js", "jsx", "ts", "tsx"].includes(ext)) {