fix endpoint prefix middleware input check

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/integration/EndpointHostPrefixMiddleware.java

@@ -125,7 +125,7 @@ private static void writeMiddleware(
                 writer.addUseImports(SmithyGoDependency.STRINGS);
                 writer.addUseImports(SmithyGoDependency.SMITHY);
                 StructureShape input = ProtocolUtils.expectInput(model, operation);
-                writer.write("input, ok := in.Parameters.($T)", symbolProvider.toSymbol(input));
+                writer.write("input, ok := in.Parameters.($P)", symbolProvider.toSymbol(input));
                 w.openBlock("if !ok {", "}", () -> {
                     writer.write("return out, metadata, fmt.Errorf(\"unknown input type %T\", in.Parameters)");
                 }).write("");