This product supports building and testing swift-format, forwarding the commands to a build script inside of swift-format's repo to handle actually invoking Swift PM. There are new command line options to support the swift-format product:
`--swiftformat`: Enables building swift-format.
`--skip-test-swiftformat': Disables running tests for swift-format after building.
Installing is intentionally not implemented because swift-format isn't ready to be installed as part of the Swift toolchain.
