Make sha256 more clear

Signed-off-by: Xuanwo <[email protected]>

Author: Xuanwo

docs/en/guides/90-community/02-rfcs/20250109-disaster-recovery.md

@@ -158,10 +158,10 @@ they will see the following files created:
 ```shell
 s3://backup/bendsave.md
 s3://backup/manifests/20250114_201500.manifest
-s3://backup/data/<block_id_0>
-s3://backup/data/<block_id_1>
-s3://backup/data/<block_id_....>
-s3://backup/data/<block_id_N>
+s3://backup/data/<sha256_of_block_0>
+s3://backup/data/<sha256_of_block_1>
+s3://backup/data/<sha256_of_block_....>
+s3://backup/data/<sha256_of_block_N>
 ```
 
 The second time users perform a backup, bendsave will generate the following files and omit existing blocks:
@@ -170,12 +170,12 @@ The second time users perform a backup, bendsave will generate the following fil
 s3://backup/bendsave.md
 s3://backup/manifests/20250114_201500.manifest
 s3://backup/manifests/20250115_201500.manifest
-s3://backup/data/<block_id_0>
-s3://backup/data/<block_id_1>
-s3://backup/data/<block_id_....>
-s3://backup/data/<block_id_N>
-s3://backup/data/<block_id_....>
-s3://backup/data/<block_id_M>
+s3://backup/data/<sha256_of_block_0>
+s3://backup/data/<sha256_of_block_1>
+s3://backup/data/<sha256_of_block_....>
+s3://backup/data/<sha256_of_block_N>
+s3://backup/data/<sha256_of_block_....>
+s3://backup/data/<sha256_of_block_M>
 ```
 
 The block id is generated by the SHA-256 checksum of the block content. So we can reuse the same block if it has been backed up before.