Format ExitCodeException stdout and stderr with UTF-8

[tomjaguarpaw]

Closes #86

Before:

ghci> readProcess_ (shell "echo привет;echo 😑 1>&2 ; exit 1")
*** Exception: Received ExitFailure 1 when running
Shell command: echo привет;echo 😑 1>&2 ; exit 1
Standard output:

пÑивеÑ
Standard error:

ð

After:

ghci> readProcess_ (shell "echo привет;echo 😑 1>&2 ; exit 1")
*** Exception: Received ExitFailure 1 when running
Shell command: echo привет;echo 😑 1>&2 ; exit 1
Standard output:

привет
Standard error:

😑

[9999years]

I think this looks OK. It should probably include the test-cases I wrote for this behavior in #88 and #89 though?

[tomjaguarpaw]

Thanks. Let's add unit tests if we need them when incorporating your whitespace changes.

[tomjaguarpaw]

Published as https://hackage.haskell.org/package/typed-process-0.2.13.0

Thanks @9999years for this contribution, and thanks to @lf- for contributing to the discussion.