Update docs about attachment path (#26883)

This change was caused by #26271, for configuration as below:
```
[attachment]
ENABLE = true
PATH = data/attachments
MAX_SIZE = 100
MAX_FILES = 5
```
Before #26271, the resolved path is ${AppWorkPath}/${attachments.PATH}
(such as `/var/lib/gitea/data/attachments`)
After #26271, the resolved path is ${AppDataPath}/${attachments.PATH}
(such as `/var/lib/gitea/data/data/attachments`)


Fix  #26864
Follow #26271

Author: CaiCandong

custom/conf/app.example.ini

@@ -1824,8 +1824,9 @@ LEVEL = Info
 ;; Currently, only `minio` is supported.
 ;SERVE_DIRECT = false
 ;;
-;; Path for attachments. Defaults to `data/attachments` only available when STORAGE_TYPE is `local`
-;PATH = data/attachments
+;; Path for attachments. Defaults to `attachments`. Only available when STORAGE_TYPE is `local`
+;; Relative paths will be resolved to `${AppDataPath}/${attachment.PATH}`
+;PATH = attachments
 ;;
 ;; Minio endpoint to connect only available when STORAGE_TYPE is `minio`
 ;MINIO_ENDPOINT = localhost:9000

docs/content/administration/config-cheat-sheet.en-us.md

@@ -822,7 +822,7 @@ Default templates for project boards:
 - `MAX_FILES`: **5**: Maximum number of attachments that can be uploaded at once.
 - `STORAGE_TYPE`: **local**: Storage type for attachments, `local` for local disk or `minio` for s3 compatible object storage service, default is `local` or other name defined with `[storage.xxx]`
 - `SERVE_DIRECT`: **false**: Allows the storage driver to redirect to authenticated URLs to serve files directly. Currently, only Minio/S3 is supported via signed URLs, local does nothing.
-- `PATH`: **data/attachments**: Path to store attachments only available when STORAGE_TYPE is `local`
+- `PATH`: **attachments**: Path to store attachments only available when STORAGE_TYPE is `local`, relative paths will be resolved to `${AppDataPath}/${attachment.PATH}`.
 - `MINIO_ENDPOINT`: **localhost:9000**: Minio endpoint to connect only available when STORAGE_TYPE is `minio`
 - `MINIO_ACCESS_KEY_ID`: Minio accessKeyID to connect only available when STORAGE_TYPE is `minio`
 - `MINIO_SECRET_ACCESS_KEY`: Minio secretAccessKey to connect only available when STORAGE_TYPE is `minio`

docs/content/administration/config-cheat-sheet.zh-cn.md

@@ -788,7 +788,7 @@ Gitea 创建以下非唯一队列：
 - `MAX_FILES`: **5**: 一次最多上传的附件数量。
 - `STORAGE_TYPE`: **local**: 附件的存储类型，`local` 表示本地磁盘，`minio` 表示兼容 S3 的对象存储服务，如果未设置将使用默认值 `local` 或其他在 `[storage.xxx]` 中定义的名称。
 - `SERVE_DIRECT`: **false**: 允许存储驱动器重定向到经过身份验证的 URL 以直接提供文件。目前，只支持 Minio/S3 通过签名 URL 提供支持，local 不会执行任何操作。
-- `PATH`: **data/attachments**: 存储附件的路径，仅当 STORAGE_TYPE 为 `local` 时可用。
+- `PATH`: **attachments**: 存储附件的路径，仅当 STORAGE_TYPE 为 `local` 时可用。如果是相对路径，将会被解析为 `${AppDataPath}/${attachment.PATH}`.
 - `MINIO_ENDPOINT`: **localhost:9000**: Minio 端点以连接，仅当 STORAGE_TYPE 为 `minio` 时可用。
 - `MINIO_ACCESS_KEY_ID`: Minio accessKeyID 以连接，仅当 STORAGE_TYPE 为 `minio` 时可用。
 - `MINIO_SECRET_ACCESS_KEY`: Minio secretAccessKey 以连接，仅当 STORAGE_TYPE 为 `minio` 时可用。