[doc](disk)fix disk capacity doc error (#20506)

docs/en/docs/admin-manual/maint-monitor/disk-capacity.md

@@ -77,8 +77,8 @@ When disk capacity **more than** `storage_flood_stage_usage_percent`, **or** dis
 **Flood Stage:**
 
 ```
-capacity_used_percent_flood_stage: default value is 95 (95%).
-capacity_min_left_bytes_flood_stage: default value is 1GB.
+storage_flood_stage_usage_percent: default value is 90 (90%).
+storage_flood_stage_left_capacity_bytes: default value is 1GB.
 ```
 
 When disk capacity **more than** `storage_flood_stage_usage_percent`, **and** disk free capacity **less than** `storage_flood_stage_left_capacity_bytes`, the following operations on this disk will be prohibited:

docs/zh-CN/docs/admin-manual/maint-monitor/disk-capacity.md

@@ -77,8 +77,8 @@ storage_flood_stage_left_capacity_bytes 默认 1GB。
 **危险水位：**
 
 ```text
-capacity_used_percent_flood_stage 默认 95 (95%)。
-capacity_min_left_bytes_flood_stage 默认 1GB。
+storage_flood_stage_usage_percent 默认 90 (90%)。
+storage_flood_stage_left_capacity_bytes 默认 1GB。
 ```
 
 当磁盘空间使用率**大于** `storage_flood_stage_usage_percent`，**并且** 磁盘空间剩余大小**小于** `storage_flood_stage_left_capacity_bytes` 时，该磁盘上的以下操作会被禁止：

fe/fe-common/src/main/java/org/apache/doris/common/Config.java

@@ -783,7 +783,7 @@ public class Config extends ConfigBase {
     @ConfField(mutable = true, masterOnly = true)
     public static int storage_flood_stage_usage_percent = 95;
     @ConfField(mutable = true, masterOnly = true)
-    public static long storage_flood_stage_left_capacity_bytes = 1 * 1024 * 1024 * 1024; // 100MB
+    public static long storage_flood_stage_left_capacity_bytes = 1 * 1024 * 1024 * 1024; // 1GB
 
     // update interval of tablet stat
     // All frontends will get tablet stat from all backends at each interval