Font fallback with symbols as primary font results in weird cell spacing

[ryancragun]

I haven't had time to bisect this but the change that caused it was merged in the last 24 hours.

If you set a symbols font as your primary and rely on fallback to an actual font you get super weird cell spacing.

Ghostty 1.0.2-main+051fed0c

Version
  - version: 1.0.2-main+051fed0c
  - channel: tip
Build Config
  - Zig version: 0.13.0
  - build mode : builtin.OptimizeMode.ReleaseFast
  - app runtime: apprt.Runtime.none
  - font engine: font.main.Backend.coretext
  - renderer   : renderer.Metal
  - libxev     : main.Backend.kqueue

Minimal config:

font-family = Symbols Nerd Font Mono
font-family = Monaco

If I reverse the ordering things render as one would expect:

My motivation for doing this in the first place is so that symbols are always consistent from that font.

[mitchellh]

The primary font determines the cell grid so this is working as intended. I think we should update the documentation to note this though.