add default help text for new ts option

Author: wing328

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AbstractTypeScriptClientCodegen.java

@@ -54,7 +54,7 @@ public AbstractTypeScriptClientCodegen() {
         // mapped to String as a workaround
         typeMapping.put("binary", "string");
 
-        cliOptions.add(new CliOption(CodegenConstants.MODEL_PROPERTY_NAMING, CodegenConstants.MODEL_PROPERTY_NAMING_DESC));
+        cliOptions.add(new CliOption(CodegenConstants.MODEL_PROPERTY_NAMING, CodegenConstants.MODEL_PROPERTY_NAMING_DESC).defaultValue("camelCase"));
 
 
 	}