std.builtin.TypeInfo.Pointer is missing information on bit-alignment

[rohlem]

Currently, @typeInfo(* align(a:b:c) u32).Pointer.alignment is simply a comptime_int representing the first (byte) alignment value, the other two are ignored.
This limits generic reflection code in introspecting them. To even differentiate them from byte-aligned pointer types, you need to reconstruct the byte-aligned type and compare them.

I assume this extension (and inversely supporting generic creation via @Type) was already planned and just not a priority (as packed structs still have more pressing bugs), so this is just a tracking issue.