Enable search in documentation

[rafaelbeckel]

The documentation is implemented in mdbook, which provides a search feature. Why is it not enabled for wasm-bindgen?

It's tedious to browse everything when trying to find something specific.

Edit

I noticed there are two published versions, one with search and the other without:

With search: https://rustwasm.github.io/wasm-bindgen/introduction.html

Without search: https://rustwasm.github.io/docs/wasm-bindgen/introduction.html