use explicit error sets for utf8Decode functions
use explicit error sets for utf8Decode functions

and run unicode tests at comptime also

zig-lang/zig,Dimenus/zig,Dimenus/zig,zig-lang/zig,raulgrell/zig,raulgrell/zig,zig-lang/zig,raulgrell/zig,andrewrk/zig,andrewrk/zig,raulgrell/zig,raulgrell/zig,Dimenus/zig