fix typo in addition_types directive name
diff --git a/src/http/modules/ngx_http_addition_filter_module.c b/src/http/modules/ngx_http_addition_filter_module.c
index 4076c53..c78361c 100644
--- a/src/http/modules/ngx_http_addition_filter_module.c
+++ b/src/http/modules/ngx_http_addition_filter_module.c
@@ -45,7 +45,7 @@
       offsetof(ngx_http_addition_conf_t, after_body),
       NULL },
 
-    { ngx_string("addtion_types"),
+    { ngx_string("addition_types"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
       ngx_http_types_slot,
       NGX_HTTP_LOC_CONF_OFFSET,