kotlin client: add docstring to new function (#22025)

* kotlin client: add docstring

* fix

Author: wing328

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinClientCodegen.java

@@ -996,6 +996,7 @@ public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs)
         }
         return objs;
     }
+
     private Stream<List<CodegenProperty>> getAllVarProperties(CodegenModel model) {
         return Stream.of(model.vars, model.allVars, model.optionalVars, model.requiredVars, model.readOnlyVars, model.readWriteVars);
     }
@@ -1119,6 +1120,11 @@ public void postProcessParameter(CodegenParameter parameter) {
         adjustEnumRefDefault(parameter);
     }
 
+    /**
+     * Properly set the default value for enum (reference).
+     *
+     * @param param codegen parameter
+     */
     private void adjustEnumRefDefault(CodegenParameter param) {
         if (StringUtils.isEmpty(param.defaultValue) || !(param.isEnum || param.isEnumRef)) {
             return;