[Sema] Refactor enum Codable synthesis (swiftlang#36685)

Author: drexin

include/swift/AST/DiagnosticsSema.def

@@ -2972,7 +2972,8 @@ NOTE(codable_enum_duplicate_case_name_here,none,
 NOTE(codable_enum_duplicate_parameter_name_here,none,
      "cannot automatically synthesize %0 for %1 because "
      "user defined parameter name %2 in %3 conflicts with "
-     "automatically generated parameter name", (Type, Type, Identifier, Identifier))
+     "automatically generated parameter name",
+     (Type, Type, Identifier, Identifier))
 
 WARNING(decodable_property_will_not_be_decoded, none,
         "immutable property will not be decoded because it is declared with "

include/swift/AST/KnownIdentifiers.def

@@ -142,6 +142,7 @@ IDENTIFIER(Type)
 IDENTIFIER(type)
 IDENTIFIER(typeMismatch)
 IDENTIFIER(underlyingError)
+IDENTIFIER(unsafelyUnwrapped)
 IDENTIFIER(Value)
 IDENTIFIER(value)
 IDENTIFIER_WITH_NAME(value_, "_value")