Changes:

• The javac flag -XDaddTypeAnnotationsToSymbol=true is now required for Error Prone invocations on JDK 21, to enable the javac fix for JDK-8225377: type annotations are not visible to javac plugins across compilation boundaries. See https://github.com/google/error-prone/issues/5426 for details.
• Remove deprecated value attribute from @IncompatibleModifiers and @RequiredModifiers (https://github.com/google/error-prone/issues/2122)
• Error Prone API changes to encapsulate references to internal javac APIs for end position handling (EndPosTable, DiagnosticPosition) (https://github.com/google/error-prone/commit/5440bb4bcd9d3455a131d863b09f71cfea8a346b, https://github.com/google/error-prone/commit/06c2905e03ade5e1564b5c67d44e2e34bfe5b8e4, https://github.com/google/error-prone/commit/f3915ec322fa7f190c670f6a30bd476f463d8967)