Use highlighted version of the tab icon in the bottom file system dock

editor/filesystem_dock.cpp

@@ -584,7 +584,7 @@ void FileSystemDock::_notification(int p_what) {
 			file_list_search_box->set_right_icon(get_editor_theme_icon(SNAME("Search")));
 			file_list_button_sort->set_icon(get_editor_theme_icon(SNAME("Sort")));
 
-			button_dock_placement->set_icon(get_editor_theme_icon(SNAME("GuiTabMenu")));
+			button_dock_placement->set_icon(get_editor_theme_icon(SNAME("GuiTabMenuHl")));
 
 			if (is_layout_rtl()) {
 				button_hist_next->set_icon(get_editor_theme_icon(SNAME("Back")));