chore: new @intCast syntax

[Hanaasagi]

Zig 0.11.0-dev.3853 has changed @intCast syntax. The return value type could be inferred.

• Doc: https://ziglang.org/documentation/master/#intCast
• Related to Infer destination type of cast builtins using result type ziglang/zig#16163

[Hejsil]

I'm not sure all my suggestions will compile, but I think we can avoid quite a few of these @as

[Hejsil]

Thanks 👍

[Hanaasagi]

I found that using the increment operator, the type could be inferred.

        year += @intCast(delta.years);

However, if written as follows:

        year = year + @intCast(delta.years);

The type could not be inferred.

Tested in 0.11.0-dev.3853+cc2daae47. Perhaps this issue will be addressed in future updates of Zig.