Consider removing defaults for Program/Args

[JeremyRand]

I'd suggest removing the defaults for Program and Args.

heteronculous-horklump/main.go

Lines 35 to 37 in e72d0ed

	Program string `default:"curl"`
	SocksTcp string `default:"127.0.0.1:9050"`
	Args string `default:"--proxy,socks5h://localhost:9050,https://google.com"`

If the user doesn't explicitly choose a program to run, I think that should yield an error rather than running some command that the user didn't ask for (otherwise it seems like a potential footgun).

The default SocksTcp is fine, since it'll be correct for the vast majority of users.