Allow prefix key binding to accept an array, like every other binding in [keys]

[tulbox]

idea / problem

Every action binding in [keys] takes an array. prefix doesn't:

[keys]
prefix = ["ctrl+b", "f12"]

config parse error at line 7, column 10
invalid type: sequence, expected a string
; using defaults

So prefix = "f12" silently costs me ctrl+b. herdr config check reports config: ok, because it is ok. It's just not what I want.

What I want is both keys live at once. The workaround for me is via kitty.conf instead:

map f12 send_text all \x02

That works, and I can use it, but it'd be much nicer to have it directly in the herdr config.

Separate and smaller, from the same error message: ; using defaults. One bad line drops every custom keybinding, not just the line that failed. A per-key fallback would be better.

Environment: herdr 0.7.5-preview.2026-07-21-0f10e145, preview channel, macOS 26.5.2, kitty 0.47.4.

requested change

The ability to have an array of prefix keys instead of a single one (like all the other bindings allow):

[keys]
prefix = ["ctrl+b", "f12"]

why you want this

So I can have two prefix keys (prefer f12 on desktop, but ctrl-b works way better on remote iOS apps like Moshi).