The guide pages under lib/elixir/pages are not doctests, so some
example outputs drifted from what current Elixir prints. I re-ran
each example on main (1.21.0-dev, OTP 29) with a clean IEx and
updated the blocks to match the actual output. Also fixes two typos.
Map ordering examples were left untouched since small-map print
order is not guaranteed across OTP versions.
Signed-off-by: Patric Vinicios <psdev7@gmail.com>