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This Pull Request integrates an `ICU4X` data provider API in our codebase, to make use of the internationalization APIs that this crate provides.
It changes the following:
- Creates an API for pluggable icu data providers at `Context` creation, adding an `Icu` struct to store the provider (and some other internationalization tools) at runtime.
- Slightly changes locale related functions to preserve the `Locale` type and ensure correctness. (Will make some other changes related to this).
- Integrates the `sys_locale` crate to fetch the current default locale of an user instead of always returning `en-US`.
This Pull Request closes#1948.
It changes the following:
- set `readme` in `boa_engine` so `README.md` will be published to crates.io
- remove unnecessary `exclude` field from `Cargo.toml` in all apps
I was unsure whether using a path outside of the workspace root was allowed for `readme` since it [doesn't get included in the release tarball](https://github.com/rust-lang/cargo/issues/5911), but this exact path is used by [juniper](https://github.com/graphql-rust/juniper/blob/master/juniper/Cargo.toml#L13) and [seems to work there](https://crates.io/crates/juniper). I believe `cargo publish` does a bit more than just uploading the tarball, including pulling the `readme` from any arbitrary path.
The default behaviour of `cargo package`/`cargo publish` if neither `exclude` or `include` is specified is to include all files from the package root, excluding
- dotfiles
- .gitignore'd files
- subpackages (any subdirectory with a `Cargo.toml` file)
- the `/target` directory
There's no need to explicitly exclude files from the parent directory since they're already excluded by default. This can be verified by running `cargo package --list` inside any workspace app:
```plain
$ cd boa_wasm
$ cargo package --list
.gitignore
Cargo.toml
Cargo.toml.orig
src/lib.rs
```
You can read more [here](https://doc.rust-lang.org/cargo/reference/manifest.html#the-exclude-and-include-fields).