wrapCommand abstract method
Wraps a user-typed line so it runs and is followed by tail (a marker)
as one logical unit. interactive enables terminal-echo handling where the
dialect needs it (POSIX only: no tty echo to toggle over a pipe;
PowerShell's own prompt and echo of the line are filtered instead, see
echoesInput).
Implementation
String wrapCommand(
String line, {
required bool interactive,
required String tail,
});