Add Windows Defender preference keywords

When running into the first problem with the new Windows Defender
tooling, it was unclear where to search in preferences, since no
matching keyword is defined.

bundles/org.eclipse.ui.ide/plugin.properties

@@ -243,7 +243,7 @@ PreferenceKeywords.Close = close
 PreferenceKeywords.Dirty = dirty
 PreferenceKeywords.Keys = binding command scheme emacs shortcut keybinding keymap
 PreferenceKeywords.Perspectives = open view switch
-PreferenceKeywords.StartupAndShutdown = exit workbench plug-in plugin refresh
+PreferenceKeywords.StartupAndShutdown = exit workbench plug-in plugin refresh defender performance
 PreferenceKeywords.Workspace = refresh polling native hooks name system explorer open close project line delimiter
 PreferenceKeywords.Workspace.Build = build order save automatically parallel simultaneous cycles
 PreferenceKeywords.LinkedResources = path drag drop copy virtual folder variable