documentation: Minor fixes

docs/configuration/index.zh.md

@@ -9,6 +9,7 @@ sing-box 使用 JSON 作为配置文件格式。
   "log": {},
   "dns": {},
   "ntp": {},
+  "certificate": {},
   "endpoints": [],
   "inbounds": [],
   "outbounds": [],
@@ -24,6 +25,7 @@ sing-box 使用 JSON 作为配置文件格式。
 | `log`          | [日志](./log/)           |
 | `dns`          | [DNS](./dns/)          |
 | `ntp`          | [NTP](./ntp/)          |
+| `certificate`  | [证书](./certificate/)   |
 | `endpoints`    | [端点](./endpoint/)      |
 | `inbounds`     | [入站](./inbound/)       |
 | `outbounds`    | [出站](./outbound/)      |