Update for Zig 0.13.0-dev.351+64ef45eb0

Update for Zig 0.12.0-dev.3194+4ba4f94c9.

Use better name for add.

Update for latest Zig master.

Zig commit: 8f3ccbbe367bea66d7f0f364a957870eb2cc95a0

This is the path to 0.12.0.

Also added the HTML to the repo, so we can keep them in sync.

markdowned

Point to tutorial

initial commit