docs issue at: RichText 组件参考

[Nicholas10128]

filePath: zh/ui-system/components/editor/richtext.md
content:

I follow the direction about how to use outline on RichText which is
"outline | Specify the font outline, you could customize the outline color and width by using the color and width attribute. | <outline color=red width=4>A label with outline</outline> | If you don't specify the color or width of outline, the default color value is #ffffff and the default width is 1."
But it caused deprecated warning "'LabelOutline.color' is deprecated. (Please use Label.outlineColor instead.)
debug.ts:78
'LabelOutline.width' is deprecated. (Please use Label.outlineWidth instead.)" on 3.8.2.