By raising this baseline the project can now use Java 17 language features such
as text blocks, switch expressions and `instanceof` pattern matching. The code
has been updated to make use of these constructs.
Note that the project can still be used by builds that target an older version
of Java, as long as those builds are executed using JDK 17+.
The new `@TypeMigration` annotation can be placed on Refaster rule
collections to indicate that they migrate most or all public methods of
an indicated type. The new check validates the claim made by the
annotation.
