tmf: Fix non-externalized string warning in AbstractSelectTreeViewer2

Fix the Eclipse warning [1] below in AbstractSelectTreeViewer2.

[1] "Non-externalized string literal; it should be followed by
//$NON-NLS-<n>$".

Change-Id: Ifc940a7b6f44de8cbe00049c6f740a36d9444557
Signed-off-by: Marco Miller <marco.miller@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/c/tracecompass/org.eclipse.tracecompass/+/201540
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>

tmf/org.eclipse.tracecompass.tmf.ui/src/org/eclipse/tracecompass/tmf/ui/viewers/tree/AbstractSelectTreeViewer2.java

@@ -328,7 +328,7 @@ protected void contentChanged(ITmfTreeViewerEntry rootEntry) {
     }
 
     private void refreshTree(@NonNull FlowScopeLog parent) {
-        try (FlowScopeLog refresh = new FlowScopeLogBuilder(LOGGER, Level.FINE, getClass().getSimpleName() + "#treeRefresh()").setParentScope(parent).build()) {
+        try (FlowScopeLog refresh = new FlowScopeLogBuilder(LOGGER, Level.FINE, getClass().getSimpleName() + "#treeRefresh()").setParentScope(parent).build()) { //$NON-NLS-1$
             getTreeViewer().refresh();
         }
     }