message: Fix the broken link for WASI ABI
diff: @@ -99,5 +99,5 @@ of links that may help you:
  * [WASI C API header
  file](https://github.com/WebAssembly/wasi-libc/blob/main/libc-bottom-half/headers/public/wasi/api.h),
  * [WASI Application Binary Interface
  - (ABI)](https://github.com/WebAssembly/WASI/blob/main/design/application-abi.md),
  + (ABI)](https://github.com/WebAssembly/WASI/blob/main/legacy/application-abi.md),
  where we learn about `_start` and `_initialize` (for _reactors_) for example.
  