hx 0.11.0

> If you use the Helix editor, or installed hx via Homebrew: this release
> may install hx under the name hxs instead of hx. Helix's binary is also
> called hx, and hx now steps aside rather than colliding. Every command works
> the same, spelled hxs. The installer tells you when it does this; Homebrew
> does it unconditionally, so brew upgrade replaces an existing hx with hxs.
> Run hx doctor (or hxs doctor) to see which names are in play on your
> machine, and see the Changed section below for how to keep the short name.

Changed
• The binary name is no longer fixed to hx. The Helix editor's binary is
also called hx and ships in most distributions, so a machine can end up with
two executables under one name — whichever comes first on PATH wins and the
other becomes unreachable. hx now adapts instead of colliding.
• The CLI derives its command name from argv[0], so help text, usage,
parse errors, completions and man pages all follow the name the binary was
actually installed under. Previously these were hardcoded：a renamed binary
printed hx throughout its help and, worse, generated shell completions
registered against hx — a command absent from that machine.
(#19)
• install.sh probes PATH and installs as hxs when something else
already owns hx, reporting it plainly. It distinguishes an upgrade from a …