fix estree plugin type declaration (#15018)

Co-authored-by: fisker Cheung <lionkay@gmail.com>

changelog_unreleased/api/15018.md

@@ -0,0 +1,3 @@
+#### Fix plugins/estree.d.ts to make it a module (#15018 by @kingyue737)
+
+Add `export {}` in `plugins/estree.d.ts` to fix the "File is not a module" error

scripts/build/build-types.js

@@ -38,10 +38,10 @@ async function buildPluginTypes({ file: { input, output } }) {
   const parserNames = Object.keys(plugin.parsers ?? {});
 
   // We only add `parsers` to types file, printers should not be used alone
-  // For `estree` plugin, we just write an empty file
+  // For `estree` plugin, we just export an empty object to ensure it treated as a module
   const code =
     parserNames.length === 0
-      ? ""
+      ? "export {};"
       : outdent`
         import { Parser } from "../index.js";
 
@@ -52,10 +52,10 @@ async function buildPluginTypes({ file: { input, output } }) {
               `${" ".repeat(2)}${toPropertyKey(parserName)}: Parser;`,
           )
           .join("\n")}
-        };\n
+        };
       `;
 
-  await writeFile(path.join(DIST_DIR, output.file), code);
+  await writeFile(path.join(DIST_DIR, output.file), `${code}\n`);
 }
 
 function buildTypes(options) {