Add obsolete message and version

Author: fredericDelaporte

src/NHibernate/Action/BulkOperationCleanupAction.cs

@@ -147,14 +147,16 @@ private void EvictEntityRegions()
 
 		#endregion
 
-		[Obsolete]
+		// Since v5.2
+		[Obsolete("This method has no more usage in NHibernate and will be removed in a future version.")]
 		public virtual void Init()
 		{
 			EvictEntityRegions();
 			EvictCollectionRegions();
 		}
 
-		[Obsolete]
+		// Since v5.2
+		[Obsolete("This method has no more usage in NHibernate and will be removed in a future version.")]
 		public virtual async Task InitAsync(CancellationToken cancellationToken)
 		{
 			await EvictEntityRegionsAsync(cancellationToken);

src/NHibernate/Hql/Ast/ANTLR/Exec/AbstractStatementExecutor.cs

@@ -59,7 +59,8 @@ protected virtual void CoordinateSharedCacheCleanup(ISessionImplementor session)
 			}
 		}
 
-		[Obsolete]
+		// Since v5.2
+		[Obsolete("This method has no more actual async calls to do, use its sync version instead.")]
 		protected virtual Task CoordinateSharedCacheCleanupAsync(ISessionImplementor session, CancellationToken cancellationToken)
 		{
 			cancellationToken.ThrowIfCancellationRequested();