Support for Zig 0.14.0

[TotoShampoin]

With Zig 0.14.0 on its way, a few changes were made to the std. Namely, @typeinfo().Struct was replaced by @typeinfo().@"struct"

This PR makes that change in zig-generic.zig

While the PR is indeed aimed to pull into master, I suggest either making the pull into a new branch, or waiting until 0.14 releases to actually pull.