Fixes#215.
delete.zig's item replacement/refresh code is pretty awful and may be
buggy in some edge cases. Existing refresh infrastructure wasn't
designed to update an individual file.
Haven't mentioned the new -O flag in the examples section yet. Let's
first keep it as a slightly lower-profile feature while the format gains
wider testing and adoption.
Still not a fan of roff, but even less a fan of build system stuff and a
dependency on a tool that is getting less ubiquitous over time.
I've removed the "hard links" section from the man page for now. Such a
section might be useful, but much of it was outdated.