Fix a doxygen warning

git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1839872 13f79535-47bb-0310-9956-ffa450edef68

Author: Christophe Jaillet

include/apr_json.h

@@ -366,7 +366,7 @@ APR_DECLARE(apr_json_value_t *)
  * @return Returns the first value, or NULL if not an array, or the array is
  *   empty.
  */
-APR_DECLARE(apr_json_value_t *) apr_json_array_first(const apr_json_value_t *obj)
+APR_DECLARE(apr_json_value_t *) apr_json_array_first(const apr_json_value_t *arr)
         __attribute__((nonnull(1)));;
 
 /**