revert: rename defineRules to defineEslintConfig

Author: johnsoncodehk

README.md

@@ -180,11 +180,11 @@ Convert ESLint rules via `@tsslint/eslint`.
 
 ```ts
 import { defineConfig } from '@tsslint/config';
-import { defineEslintConfig } from '@tsslint/eslint';
+import { defineRules } from '@tsslint/eslint';
 
 export default defineConfig({
   rules: {
-    ...defineEslintConfig({
+    ...defineRules({
       'no-unused-vars': 'error',
       '@typescript-eslint/no-explicit-any': 'warn',
     }),