run `zig fmt`

[rohlem]

I ran the zig fmt formatting command (using newest zig version 0.10.0-dev390+0866fa9d1) in a local project for consistency, and thought you might want to have the repo be in canonical form too. If not, feel free to close this PR.

It's really just whitespace changes, though I inserted a trailing comma at one point to make it preserve a line break.