Add usage examples of arrays

Nice project! They nicely demonstrate to use all of the various types, except C arrays.

Look at the existing type examples in the repository, likely in a directory like 'examples' or 'docs'. Find where C arrays are currently missing. Create a new example file showing how to use arrays with Deno FFI, referencing the Deno FFI documentation for correct syntax. Test the example runs with Deno to ensure it works.

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