feat: add settings for flat config (#166)

Author: sxzz

src/flat-config/index.d.ts

@@ -55,6 +55,13 @@ export interface FlatESLintConfigItem {
    * @see [Configuring rules](https://eslint.org/docs/latest/user-guide/configuring/configuration-files-new#configuring-rules)
    */
   rules?: Rules;
+
+  /**
+   * An object containing name-value pairs of information that should be available to all rules.
+   *
+   * @see [Configuring shared settings](https://eslint.org/docs/latest/user-guide/configuring/configuration-files-new#configuring-shared-settings)
+   */
+  settings?: Record<string, any>;
 }
 
 /**

tests/define.test-d.ts

@@ -41,6 +41,7 @@ describe('define', () => {
           ignores: [],
           plugins: {},
           rules: {},
+          settings: {},
         },
       ]),
     ).toEqualTypeOf<FlatESLintConfig[]>();