ruby toml file example is now consistent with dir structure

[jpshackelford]

The ruby tutorial was explicit about the directory structure including head-wasm32-unknown-wasi-full but did not mention renaming and moving of files so as to make it work with the toml file as listed. To help a first time reader of toml understand its various properties, we update it to match the directory structure as described earlier in the tutorial.

Signed-off-by: John-Mason P. Shackelford [email protected]

[itowlson]

@adamreese bumping - sorry to nag but I don't think we have anyone else qualified to review this