Terminal(teletype?) detection implementation is wrong

[Krysztal112233]

The current implementation relies on scanning /proc/{pid}/fd, which works well in privileged mode because all fd's are accessible.

But the result is incorrect when used in normal user mode. For example:

❯ pgrep -t tty1
2384
❯ cargo run -q pgrep -t tty1
(*empty here)

And affects the following commands

• pgrep
• pidof
• pkill (in future)