typings: add missing binding function writeFileUtf8()

PR-URL: #54110
Reviewed-By: Daeyeon Jeong <daeyeon.dev@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>

typings/internalBinding/fs.d.ts

@@ -286,6 +286,7 @@ export interface FsBinding {
   utimes: typeof InternalFSBinding.utimes;
   writeBuffer: typeof InternalFSBinding.writeBuffer;
   writeBuffers: typeof InternalFSBinding.writeBuffers;
+  writeFileUtf8: typeof InternalFSBinding.writeFileUtf8;
   writeString: typeof InternalFSBinding.writeString;
 
   getFormatOfExtensionlessFile: typeof InternalFSBinding.getFormatOfExtensionlessFile;