- abandon @NullableByDefault,
- add a boolean parameter to @NonNullByDefault for canceling defaults
  - implementation uses new TagBits.AnnotationNullUnspecifiedByDefault to represent @NonNullByDefault(false), 
  - similarly, Constants NULL_UNSPECIFIED represents explicit absence of a null annotation
- new warning for redundant @NonNull within a scope with default
- new error if annotation name is not a FQN
- abandon warning token "nullcontract", subsume under "null"

5 files changed