fix type mismatch in std.net.StreamServer
fix type mismatch in std.net.StreamServer

Parameter in std.os.listen is u31.

Fixes ziglang#6775

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