quote retuned text values

[akihiro17]

Quote returned text values to prevent word splitting.

reproduction script

import { words, join } from "std"

main(args) {
  echo words(join(["hello", "world"], " "))
}

before

hello

after

hello world

ref. https://www.shellcheck.net/wiki/SC2086

[Ph0enixKM]

Thanks for contributing @akihiro17! Merging