fix comment

src/http/ngx_http_special_response.c

diff --git a/src/http/ngx_http_special_response.c b/src/http/ngx_http_special_response.c
index 20a8fa7..5671f9b 100644
--- a/src/http/ngx_http_special_response.c
+++ b/src/http/ngx_http_special_response.c
@@ -307,7 +307,7 @@
     ngx_string(ngx_http_error_495_page), /* 495, https certificate error */
     ngx_string(ngx_http_error_496_page), /* 496, https no certificate */
     ngx_string(ngx_http_error_497_page), /* 497, http to https */
-    ngx_string(ngx_http_error_404_page), /* 498, invalid host name */
+    ngx_string(ngx_http_error_404_page), /* 498, canceled */
     ngx_null_string,                     /* 499, client has closed connection */
 
     ngx_string(ngx_http_error_500_page),