br: remove experimental feature notice for encryption to GA in v8.5 (#19366)

Author: Tristan1900

br/br-pitr-manual.md

@@ -91,10 +91,6 @@ tiup br log start \
 
 ### Encrypt the log backup data
 
-> **Warning:**
->
-> Currently, this feature is experimental. It is not recommended that you use it in production environments. If you find a bug, you can report an [issue](https://github.com/pingcap/tidb/issues) on GitHub.
-
 BR enables you to encrypt log backup data before uploading it to your backup storage.
 
 Starting from TiDB v8.4.0, you can encrypt log backup data by passing the following parameters in the log backup command, which is similar to [snapshot backup encryption](/br/br-snapshot-manual.md#encrypt-the-backup-data):
@@ -472,10 +468,6 @@ Restore KV Files <--------------------------------------------------------------
 
 ### Restore encrypted log backup data
 
-> **Warning:**
->
-> Currently, this feature is experimental. It is not recommended that you use it in production environments. If you find a bug, you can report an [issue](https://github.com/pingcap/tidb/issues) on GitHub.
-
 To restore encrypted log backup data, you need to pass the corresponding decryption parameters in the restore command. Make sure that the decryption parameters are the same as those used for encryption. If the decryption algorithm or key is incorrect, the data cannot be restored.
 
 The following is an example:

br/br-snapshot-manual.md

@@ -135,10 +135,6 @@ When the backup and restore feature backs up data, it stores statistics in JSON
 
 ## Encrypt the backup data
 
-> **Warning:**
->
-> This is an experimental feature. It is not recommended that you use it in the production environment.
-
 BR supports encrypting backup data at the backup side and [at the storage side when backing up to Amazon S3](/br/backup-and-restore-storages.md#amazon-s3-server-side-encryption). You can choose either encryption method as required.
 
 Since TiDB v5.3.0, you can encrypt backup data by configuring the following parameters:
@@ -279,10 +275,6 @@ ADMIN RELOAD BINDINGS;
 
 ## Restore encrypted snapshots
 
-> **Warning:**
->
-> This is an experimental feature. It is not recommended that you use it in the production environment.
-
 After encrypting the backup data, you need to pass in the corresponding decryption parameters to restore the data. Ensure that the decryption algorithm and key are correct. If the decryption algorithm or key is incorrect, the data cannot be restored. The following is an example:
 
 ```shell