chore: hostHeaders default value is empty string (#5413)

pick from #5412

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Documentation**
	- Updated plugin links to reflect the current repository addresses.
- Improved clarity on host header behavior and configuration, including
guidance for reverse proxy setups.
- Enhanced textual explanations for properties related to host and
protocol.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: fengmk2

site/docs/basics/controller.md

@@ -315,7 +315,7 @@ If user request exceeds the maximum length for parsing that we configured, the f
 
 ### Acquiring the Submitted Files
 
-The `body` in the request can carry parameters as well as files. Generally speaking, our browsers always send files in `multipart/form-data`, and we now have two kinds of ways supporting submitting and acquiring files with the help of the framework's plugin [Multipart](https://github.com/eggjs/multipart).
+The `body` in the request can carry parameters as well as files. Generally speaking, our browsers always send files in `multipart/form-data`, and we now have two kinds of ways supporting submitting and acquiring files with the help of the framework's plugin [Multipart](https://github.com/eggjs/egg-multipart).
 
 - #### `File` Mode:
   If you have no ideas about Nodejs's Stream at all, the `File` mode suits you well:
@@ -589,7 +589,7 @@ module.exports = {
 
 **Notice：`fileExtensions` will be IGNORED when `whitelist` is overwritten.**
 
-For more tech details about this, please refer [@eggjs/multipart](https://github.com/eggjs/multipart).
+For more tech details about this, please refer [Egg-Multipart](https://github.com/eggjs/egg-multipart).
 
 ### `header`
 
@@ -605,9 +605,10 @@ Specially when we set `config.proxy = true` to deploy the application behind the
 
 #### `ctx.host`
 
-Reads the header's value configured by `config.hostHeaders` firstly, if fails, then it tries to get the value of host header, if fails again, it returns an empty string.
+Reads the header's value configured by `config.hostHeaders` firstly, if fails, then it tries to get the value of `host` header, if fails again, it returns an empty string.
 
-`config.hostHeaders` defaults to `x-forwarded-host`.
+`config.hostHeaders` defaults to `''`.
+If the application is deployed behind a reverse proxy and `config.proxy = true` is configured, a correct value needs to be configured here, such as `x-forwarded-host`. Please configure it according to the actual value of the proxy.
 
 #### `ctx.protocol`
 
@@ -684,7 +685,7 @@ module.exports = {
 
 By using Cookie, we can create an individual Session specific to every user to store user identity information, which will be encrypted then stored in Cookie to perform session persistence across requests.
 
-The framework builds in [Session](https://github.com/eggjs/session) plugin, which provides `ctx.session` for us to get or set current user's Session.
+The framework builds in [Session](https://github.com/eggjs/egg-session) plugin, which provides `ctx.session` for us to get or set current user's Session.
 
 ```js
 class PostController extends Controller {

site/docs/basics/controller.zh-CN.md

@@ -598,7 +598,8 @@ module.exports = {
 
 此 Getter 优先读取 `config.hostHeaders` 中配置的 header 值。若无法获取，则尝试读取 `host` 这个 header 的值。若仍旧获取不到，则返回空字符串。
 
-`config.hostHeaders` 的默认配置为 `x-forwarded-host`。
+`config.hostHeaders` 的默认配置为 `''` 空字符串。
+如果应用部署在反向代理后面，并且配置了 `config.proxy = true`，需要在这里配置一个正确的值，例如 `x-forwarded-host`，请按照代理真实值配置。
 
 #### `ctx.protocol`