CLEANUP: cli: make "show fd" use its own context

The "show fd" command used to rely on cli.i0 for the fd, and st2 just
to decide whether to stop after the first value or not. It could have
been possible to decide to use just a negative integer to dump a single
value, but it's as easy and more durable to declare a two-field struct
show_fd_ctx for this.
1 file changed