IGNITE-15074 : Fix documentation for support encrypted snapshots (#9238)

Author: Vladsz83

docs/_docs/security/tde.adoc

@@ -14,8 +14,6 @@
 // limitations under the License.
 = Transparent Data Encryption
 
-WARNING: This feature is in beta and not recommended for use in production environments.
-
 == Overview
 Transparent data encryption (TDE) allows users to encrypt their data at rest.
 
@@ -43,7 +41,7 @@ Transparent Data Encryption has some limitations that you should be aware of bef
 
 *Snapshots and Recovery*
 
-* No support for snapshots. Snapshots are not encrypted and it's not possible to recover from a snapshot that includes an encrypted table or cache.
+* Encryption, changing of master key or cache group key are not allowed during snapshot operations.
 
 == Configuration
 To enable encryption in the cluster, provide a master key in the configuration of each server node. A configuration example is shown below.

docs/_docs/snapshots/snapshots.adoc

@@ -253,8 +253,9 @@ The snapshot procedure has some limitations that you should be aware of before u
 
 * Snapshotting of specific caches/tables is unsupported. You always create a full cluster snapshot.
 * Caches/tables that are not persisted in Ignite Persistence are not included into the snapshot.
-* Encrypted caches are not included in the snapshot.
+* Encrypted caches in the snapshot must be encrypted with the same master key.
 * You can have only one snapshotting operation running at a time.
+* The snapshot operation is prohibited during a master key change and/or cache group key change.
 * The snapshot procedure is interrupted if a server node leaves the cluster.
 
 If any of these limitations prevent you from using Apache Ignite, then select alternate snapshotting implementations for