Where possible, development should happen in AOSP so add a hook to
remind developers of this if it looks like they're trying to do
something else.
Test: N/A
Change-Id: I211de2daad2b67a3008e40043bb2da941d13548b
The rustfmt configuration is linked to the default from
build/soong/scripts.
Bug: 157146658
Test: tried uploading badly and correctly formatted rust
Change-Id: Ie104cca1c9f309e4b46acdfabd8c2e17c35180ad