docs: Minor Update in Localization Guide

Created by: Felixnoo

Signed-off-by: Felixnoo felixliu@kubesphere.io

What type of PR is this?

/kind documentation

Does this PR introduced a user-facing change?

None

/assign @Patrick-LuoYu @FeynmanZhou Hi, I updated the localization guide to make a note that Chinese (Simplified) doesn't require localization. Please take a look, thanks.