* Align outline with new spin-off course structure
With the new structure, the section on Android is a spin-off course
from the main 3-day course on Rust Fundamentals. The Bare-metal and
Concurrency days are spin-off courses in the same way.
* Explain new course structure
* Align Bare-Metal welcome page with other deep dives
* Merge Day 4 page into Course Structure page
* Remove Day 4 Welcome page
This aligns the Concurrency in Rust section with the Bare-Metal Rust
deep dive.
* Show subsections for Android deep dive
This aligns the Rust in Android section with the other deep dives.
* Clean up welcome page and README
We now cover async Rust and the course is no longer a four day course.
* Remove reference to the old Day 4
* Remove Day 4 references from exercises
The i18n-helpers are now available as a stand-alone crate:
https://crates.io/crates/mdbook-i18n-helpers.
Because we cache the Rust binaries in our GitHub workflows, I bumped
the cache prefix to ensure we use a clean cache. Otherwise, Cargo
won’t install the new binaries in mdbook-i18n-helpers because it sees
the old ones from this repository.
* Make i18n-helpers a requirement
* Skip mdbook-gettext for mdbook-xgettext
* Gettext finds PO file based on `book.language`
* Update workflow
No need to set `preprocessor.gettext.po-file`.
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Co-authored-by: Jooyung Han <jooyung@google.com>
