privatize directed codegen

Author: JordonPhillips

codegen/plugins/types/src/main/java/software/amazon/smithy/python/codegen/types/DirectedPythonTypeCodegen.java

@@ -38,7 +38,7 @@
 import software.amazon.smithy.python.codegen.integrations.PythonIntegration;
 import software.amazon.smithy.python.codegen.writer.PythonDelegator;
 
-public class DirectedPythonTypeCodegen
+final class DirectedPythonTypeCodegen
         implements DirectedCodegen<GenerationContext, PythonSettings, PythonIntegration> {
     @Override
     public SymbolProvider createSymbolProvider(CreateSymbolProviderDirective<PythonSettings> directive) {