docs(devs-infra): remove testing-css-styles doc in Guides section (#999)

Author: ahnpnl

website/docs/guides/testing-css-styles.md

@@ -23,7 +23,6 @@ module.exports = {
       items: [
         'guides/angular-ivy',
         'guides/esm-support',
-        'guides/testing-css-styles',
         'guides/jsdom-version',
         'guides/using-with-babel',
         'guides/absolute-imports',

website/sidebars.js

@@ -51,10 +51,6 @@
           "type": "doc",
           "id": "version-8.x/guides/esm-support"
         },
-        {
-          "type": "doc",
-          "id": "version-8.x/guides/testing-css-styles"
-        },
         {
           "type": "doc",
           "id": "version-8.x/guides/jsdom-version"

website/versioned_docs/version-8.x/guides/testing-css-styles.md

@@ -51,10 +51,6 @@
           "type": "doc",
           "id": "version-9.x/guides/esm-support"
         },
-        {
-          "type": "doc",
-          "id": "version-9.x/guides/testing-css-styles"
-        },
         {
           "type": "doc",
           "id": "version-9.x/guides/jsdom-version"