Add ability to detect if stdout is a terminal

[justone]

Is your feature request related to a problem? Please describe.

I was excited by the new jet features that revealed it was possible from Graalvm to detect if stdout is a terminal. I immediately thought this same feature would allow babashka scripts that emit colored output to remove the colors if their output was not directly to the terminal.

Describe the solution you'd like

Perhaps a function called isatty that you can call like this:

(if (isatty *out)
  (println with-colors)
  (println plain))

I don't know which namespace this function should belong to. Perhaps babashka.process.

Describe alternatives you've considered

I was able to achieve a similar detection by shelling out to bash:

#!/usr/bin/env bb

(require '[babashka.process :as process])

(defn isatty
  []
  (try (process/check (process/$ {:inherit true} bash -c "if [ ! -t 1 ]; then exit 1; fi"))
       true
       (catch Exception _e
         false)))

(if (isatty)
  (println "tty")
  (println "pipe"))

[borkdude]

Another alternative is using (System/console) which returns nil if either stdin/stdout/stderr is not connected to a terminal.