Word spelling problem in `CONTRIBUTING.md`

Created by: mangoGoForward

Describe the bug In CSS, SCSS Styleguide title, the fommat of spelling is error( Using Prettier to fommat css and scss files ), and how about change Styleguides to Style Guides?

For UI issues please also add a screenshot that shows the issue.

Versions used(KubeSphere/Kubernetes) KubeSphere: Kubernetes: (If KubeSphere installer used, you can skip this)