UI: Show user-oriented tooltip for extra options panel

Show "Extra options" as tooltip for the Tool Settings Extra Options item.

Pull Request: https://projects.blender.org/blender/blender/pulls/117193

scripts/startup/bl_ui/space_topbar.py

@@ -77,6 +77,7 @@ class TOPBAR_PT_tool_settings_extra(Panel):
     bl_region_type = 'HEADER'
     bl_space_type = 'TOPBAR'
     bl_label = "Extra Options"
+    bl_description = "Extra options"
 
     def draw(self, context):
         from bl_ui.space_toolsystem_common import ToolSelectPanelHelper