Merge pull request swiftlang#77424 from rintaro/ast-use-parserdiagnostics

[NFC][AST] Remove 'usesFeatureParserDiagnostics(Decl *)' function

Author: rintaro

lib/AST/FeatureSet.cpp

@@ -103,7 +103,6 @@ UNINTERESTING_FEATURE(OpaqueTypeErasure)
 UNINTERESTING_FEATURE(PackageCMO)
 UNINTERESTING_FEATURE(ParserRoundTrip)
 UNINTERESTING_FEATURE(ParserValidation)
-UNINTERESTING_FEATURE(ParserDiagnostics)
 UNINTERESTING_FEATURE(ImplicitSome)
 UNINTERESTING_FEATURE(ParserASTGen)
 UNINTERESTING_FEATURE(BuiltinMacros)