add: Wasm text instruction

(module
  (import "console" "log" (func $log (param i32)))
  (func $main
    ;; load `10` and `3` onto the stack
    i32.const 10
    i32.const 3

    i32.add ;; add up both numbers
    call $log ;; log the result
  )
  (start $main)
)

const url = "{%wasm-url%}";
await WebAssembly.instantiateStreaming(fetch(url), { console });

;; load two numbers onto the stack
i32.const 10
i32.const 3

;; add up both numbers
i32.add

;; the top item on the stack will now be 13  (10 + 3 = 13)