Update prerequisites documentation

docs/src/SUMMARY.md

@@ -1,8 +1,7 @@
 # Summary
 
 - [Prerequisites](./prerequisites/index.md)
-  - [Rust](./prerequisites/rust.md)
-  - [npm](./prerequisites/npm.md)
+  - [npm (optional)](./prerequisites/npm.md)
 - [Project Setup](./project-setup/index.md)
   - [Using a Template](./project-setup/using-a-template.md)
   - [Manual Setup](./project-setup/manual-setup.md)

docs/src/prerequisites/index.md

@@ -1,10 +1,19 @@
 # Prerequisites
 
-To run `wasm-pack` you'll need to have both Rust and npm installed and configured.
+First you'll want to [install the `wasm-pack` CLI][wasm-pack], and `wasm-pack
+-V` should print the version that you just installed.
 
-- [Rust](/wasm-pack/book/prerequisites/rust.html)
-- [npm](/wasm-pack/book/prerequisites/npm.html)
+[wasm-pack]: https://rustwasm.github.io/wasm-pack/installer/
 
-In the future, we intend to rewrite the npm registry client bits so that the need
-for a Node runtime is eliminated. If you're excited about that work- you should
-reach out to the maintainers and get involved!
+Next, since `wasm-pack` is a build tool, you'll want to make sure you have
+[Rust][rust] installed. Make sure `rustc -V` prints out at least 1.30.0.
+
+[rust]: https://www.rust-lang.org/tools/install
+
+Finally, if you're using `wasm-pack` to install to publish to NPM, you'll want
+to [install and configure `npm`][npm]. In the future, we intend to rewrite the
+npm registry client bits so that the need for a Node runtime is eliminated. If
+you're excited about that work- you should reach out to the maintainers and get
+involved!
+
+[npm]: npm.html