Enumerate Languages And Dialect Regions

[AldaronLau]

Enumerate in Language and Region enums according to the standards.

[cjohnson19]

I've been thinking about what an ideal implementation of this would look like, but my Rust knowledge is seriously lacking in most areas. The canonical approach where one creates the enums upfront seems rough to me from a maintenance / verification perspective.

I've only done some cursory investigation, but would something like a build script which generates the enums be desirable? This would likely use a data directory as mentioned in #90 and generate rust files with the enums.

[AldaronLau]

@cjohnson19 I have a plan here but it depends on #142, and #143

By changing the repo structure to a workspace, we can add an xtask crate. You can read about xtask here: https://github.com/matklad/cargo-xtask (and see an example). I also have an xtask example in another crate I maintain: https://github.com/ardaku/stick

There's a couple reasons to not use build-scripts for this. Mostly, that I want to keep build time down, and the enum generation could potentially take a while to complete.

[cjohnson19]

@AldaronLau Thank you so much for the explanation and links to resources! :)