Error Prone 2.28.0

Error Prone nows supports the latest JDK 23 EA builds (#4412, #4415).

Closed issues:

• Improved errors for invalid check severities (#4306).
• Fix a crash with nested instanceof patterns (#4349).
• Fix a crash in JUnitIncompatibleType (#4377).
• In ObjectEqualsForPrimitives, don't suggest replacing equal with == for floating-point values (#4392).

New checks:

• DeeplyNested discourages very deeply nested code that can cause StackOverflowErrors during compilation.
• GuiceNestedCombine discourages nesting of Modules.combine(), which is unnecessary.
• PatternMatchingInstanceof migrates code to use pattern matching for instanceof
• SunApi discourages use of internal proprietary JDK APIs which may be removed from future releases.

Full Changelog: v2.27.1...v2.28.0