message: Extend run project docs
  When following the instructions, I was caught out by not having the wasm target available.
diff: # Create & Run project
  1. Install the latest stable [Rust](https://www.rust-lang.org/tools/install). (Or upgrade with `rustup update stable`.)
  +1. Install the web assembly target `rustup target add wasm32-unknown-unknown`
  1. `cargo install mzoon --git https://github.com/MoonZoon/MoonZoon --locked`
  1. `mzoon new my_counter`
  1. `cd my_counter`
  