update error msg

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: abh1sar

server/src/main/java/com/cloud/vm/snapshot/VMSnapshotManagerImpl.java

@@ -756,14 +756,14 @@ public UserVm revertToSnapshot(Long vmSnapshotId) throws InsufficientCapacityExc
 
         if (userVm.getState() == VirtualMachine.State.Running && vmSnapshotVo.getType() == VMSnapshot.Type.Disk) {
             throw new InvalidParameterValueException(
-                    "Reverting to the Instance Snapshot is not allowed for running Instances as this would result in a Instance state change." +
-                            "For running Instances only Snapshots with memory can be reverted." +
+                    "Reverting to the Instance Snapshot is not allowed for running Instances as this would result in a Instance state change. " +
+                            "For running Instances only Snapshots with memory can be reverted. " +
                             "In order to revert to a Snapshot without memory you need to first stop the Instance.");
         }
 
         if ( userVm.getState() == VirtualMachine.State.Stopped && vmSnapshotVo.getType() == VMSnapshot.Type.DiskAndMemory) {
             throw new InvalidParameterValueException(
-                    "Reverting to the Instance Snapshot is not allowed for stopped Instances if the Snapshot contains memory." +
+                    "Reverting to the Instance Snapshot is not allowed for stopped Instances if the Snapshot contains memory. " +
                             "In order to revert to a Snapshot with memory you need to first start the Instance.");
         }