[code-infra] Simplify .stylelintrc.js

A continuation of mui/material-ui#42411

Author: oliviertassinari

package.json

@@ -43,7 +43,7 @@
     "jsonlint": "node ./scripts/jsonlint.mjs",
     "eslint": "eslint . --cache --report-unused-disable-directives --ext .js,.ts,.tsx --max-warnings 0",
     "eslint:ci": "eslint . --report-unused-disable-directives --ext .js,.ts,.tsx --max-warnings 0",
-    "stylelint": "stylelint --reportInvalidScopeDisables --reportNeedlessDisables \"docs/**/*.{js,ts,tsx}\"",
+    "stylelint": "stylelint --reportInvalidScopeDisables --reportNeedlessDisables \"docs/**/*.{js,ts,tsx}\" --ignore-path .gitignore",
     "markdownlint": "markdownlint-cli2 \"**/*.md\"",
     "valelint": "git ls-files | grep -h \".md$\" | xargs vale --filter='.Level==\"error\"'",
     "prettier": "pretty-quick --ignore-path .eslintignore --branch next",

.stylelintrc.js stylelint.config.mjs

@@ -1,13 +1,5 @@
-module.exports = {
+export default {
   extends: 'stylelint-config-standard',
-  ignoreFiles: [
-    // TypeScript declaration files contain no styles.
-    // Stylelint is also reporting parseError on `docs/types/react-docgen.d.ts`.
-    '**/*.d.ts',
-    'docs/.next/**/*',
-    'docs/export/**/*',
-    '**/node_modules/**/*',
-  ],
   rules: {
     'alpha-value-notation': null,
     'custom-property-pattern': null,