stage2: implement coercion from tuples to tuples

[nektro]

Zig Version

0.10.0-dev.3313+cff5d9c80

Steps to Reproduce

const std = @import("std");
const T = std.meta.Tuple(&.{u8});

pub fn main() void {
    foo(.{123});
}

pub fn foo(x: T) void {
    std.debug.assert(x[0] == 123);
}

Expected Behavior

./test.zig:5:10: error: TODO: implement coercion from tuples to tuples
    foo(.{123});
        ~^~~~~

Actual Behavior

No output. Successful run.