fix: Cast plugin as ESLint.Plugin

Author: nzakas

package.json

@@ -72,7 +72,7 @@
     "@types/eslint": "^9.6.0",
     "c8": "^10.1.2",
     "dedent": "^1.5.3",
-    "eslint": "^9.25.1",
+    "eslint": "^9.28.0",
     "eslint-config-eslint": "^11.0.0",
     "eslint-plugin-eslint-plugin": "^6.3.2",
     "globals": "^15.1.0",

src/index.js

@@ -57,6 +57,7 @@ const processorRulesConfig = {
 
 let recommendedPlugins, processorPlugins;
 
+/** @type {Plugin} */
 const plugin = {
 	meta: {
 		name: "@eslint/markdown",