fix: emit pub on exported go constants in typedefs

[ivov]

Exported Go constants now map to pub const in generated typedefs, consistent with how exported variables and functions already render.

Before this change, only value-enum members were emitted with pub. Standalone constants like codes.Error or trace.FlagsSampled were mapped as bare const, making it unclear from a .d.lis which top-level constants were part of the public API.

// before
const Error: Code = 1
const FlagsSampled: TraceFlags = 1

// after
pub const Error: Code = 1
pub const FlagsSampled: TraceFlags = 1

[ivov]

Released in lisette-v0.1.23