fix(api): Fix comments for wifi_s(g)et_country

The return value type should be bool in comments block of country code API internal gitlab: 7989fc6c

Author: wujiangang

include/user_interface.h

@@ -725,8 +725,8 @@ typedef struct {
  *
  * @param wifi_country_t *country: the configured country info
  *
- * @return 0 : succeed
- * @return -1 : fail
+ * @return true : succeed
+ * @return false : fail
  */
 bool wifi_set_country(wifi_country_t *country);
 
@@ -735,8 +735,8 @@ bool wifi_set_country(wifi_country_t *country);
  *
  * @param wifi_country_t *country: country info
  *
- * @return 0 : succeed
- * @return -1 : fail
+ * @return true : succeed
+ * @return false : fail
  */
 bool wifi_get_country(wifi_country_t *country);