message: Fix broken link in commands doc
diff: `wasm-pack` has several commands to help you during the process of building
  a Rust-generated WebAssembly project.
  -- `new`: This command generates a new project for you using a template. [Learn more][generate]
  +- `new`: This command generates a new project for you using a template. [Learn more][new]
  - `build`: This command builds a `pkg` directory for you with compiled wasm and generated JS. [Learn more][build]
  - `pack` and `publish`: These command will create a tarball, and optionally publish it to a registry, such as npm. [Learn more][pack-pub]
  