docs: readme: fixed 'unexpected token get_local'

[coderaiser]

According to https://developer.mozilla.org/en-US/docs/WebAssembly/Understanding_the_text_format#getting_and_setting_locals_and_parameters

Error: parseWat failed:
inline:4:7: error: unexpected token get_local, expected ).
      get_local $n1
      ^^^^^^^^^
  1 const iw = require('inline-webassembly');¬
inline:5:7: error: unexpected token get_local.
      get_local $n2
      ^^^^^^^^^

    at Object.parseWat (/Users/coderaiser/webasm/node_modules/wabt/index.js:28:27363)
    at module.exports (/Users/coderaiser/webasm/node_modules/inline-webassembly/lib/index.js:20:27)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)