AST: Cut down on DescriptiveDeclKind usage in DiagnosticsClangImporter.def

(cherry picked from commit cdb2aac)

Author: AnthonyLatsis

include/swift/AST/DiagnosticsClangImporter.def

@@ -279,7 +279,8 @@ ERROR(conforms_to_ambiguous,none,
       "ambiguous reference to protocol '%0' in specified protocol conformance; module '%1' contains multiple protocols named '%0'", (StringRef, StringRef))
 
 ERROR(conforms_to_not_protocol,none,
-      "%0 %1 referenced in protocol conformance '%2' is not a protocol", (DescriptiveDeclKind, ValueDecl *, StringRef))
+      "%kind0 referenced in protocol conformance '%1' is not a protocol",
+      (const ValueDecl *, StringRef))
 
 ERROR(failed_base_method_call_synthesis,none,
       "failed to synthesize call to the base method %0 of type %0",